Bunkers hold a unique fascination in the minds of doomsday preppers, the sensibly cautious and the simply curious alike. They answer our ancient instinct to seek shelter and pique our interest, forcing us to think about what it would be like to live in such a paired back way. 

In uncertain times, more and more of us are prepping for the worst and building bunkers to survive whatever the world might throw at us next. But how have they evolved over the decades? And what were they like to live in?

Click or scroll on to discover incredible images of bunkers through the ages, from the trenches of the First World War, right up to modern day...

During the First World War, miles of trenches were carved into the earth along the Western Front. They were constructed from sandbags, wooden planks, woven sticks, barbed wire and – as this image shows – just about anything soldiers could get their hands on. The deep ditches were punctuated by bunkers, where troops stored weapons, artillery and food, and took shelter from bad weather and enemy fire.

As we can see, they weren't always sophisticated. These Australian soldiers were photographed on a windy outpost on Westhoek Ridge in Ypres, Belgium in 1917. They were taking shelter in a bunker made from not much more than an upturned cart and a sheet of metal.

In comparison, this British blockhouse in Southwest Africa looks positively luxurious. These bunkers were built from corrugated metal, sandbags and sand and were used to protect troops and railroad lines from guerrilla attacks. 

The 2nd Battalion of the Royal Munster Fusiliers built a great number of the distinctive shelters in South Africa during the First World War.

This was about as lavish as bunkers got in the trenches of the First World War. In this image captured in 1916, French officers discuss tactics in a relatively large underground headquarters on the Western Front.

While not sophisticated by today's standards, the bunker was made from stones or brick with a sturdy timber frame and would have been a far cry from what the average soldier was used to.

Behind the front lines, civilians found themselves taking to bunkers as fighting took place around them. These Red Cross nurses were photographed in November 1918 carrying babies down into a sandbag bomb shelter in De Panne, Belgium.

Sandbags were a popular choice for building fortifications as they were inexpensive, easy to use, offered protection from bullets and shrapnel, absorbed shock and – despite the name – could be filled with whatever earth was at hand.

It quickly became apparent that temporary housing was needed near the front lines of the war, which could be rapidly erected and easily moved. Peter Norman Nissen, a Canadian-American soldier serving with the British Army's Royal Engineers answered the call and in 1916 the Nissen hut was born.

The huts were made from curved corrugated steel sheets with either weatherboard or sometimes brick at either end. They were adapted throughout the war to meet different needs, but this image from February 1917 shows them in their most common guise, as barracks.

This British Nissen hut camp, seen in the snow at the Somme, France would have been a relatively cosy place to rest compared to a frozen trench on the front line.

Barely 20 years later, as the Second World War loomed over Europe, new designs for bunkers and shelters were explored to protect citizens from enemy attack. 

This 1938 collectors card shows a French gas-proof balloon shelter. It was one of a set of 50 cards issued by British company WD & HO Wills in preparation for the anticipated war.

This photo taken around 1939 shows a British Air Raid Precautions (ARP) warden coming out of an air raid shelter on display at the British Industries Fair.

The unusual bunker had a 'bomb deflector' on the roof, which consisted of a mound of 15 inch diameter concrete balls.

When the Blitz hit London in September 1940, everything from underground cellars and basements to Tube stations and tunnels became bunkers in which to shelter from the bombs – as this photo of children taking refuge in September 1940 shows.

The Blitz lasted for 57 days and nights, killing 28,556 people – including 7,736 children – and damaging or destroying two million homes across Britain. 

In 1938, British Prime Minister Neville Chamberlain tasked Sir John Anderson with all air raid precautions on the home front. Anderson and his engineers came up with a small, cheap shelter made from corrugated metal. Anderson Air Raid Shelters, as they became known, were sunk into the ground and earth piled on top. Free to those on a low income, around 3.6 million were built over the course of the war.

These residents of Islington, North London were snapped putting the finishing touches on their Anderson shelters under the watchful eye of a child's toy elephant, wearing his very own gas mask. 

Space inside a bomb shelter was tight, but – as this image shows – there was still enough room for Christmas decorations and a stocking for this young girl in the winter of 1940.

Despite the Luftwaffe raining bombs down on London and blackout regulations hiding homes in the dark, Santa Claus was clearly still able to find her.

With no patch of earth to be wasted in desperate times, Londoners rallied to the cry of 'Dig for Victory' and took to planting vegetables on top of their Anderson shelters.

Here, pensioner Charles Abbott tends to his crop of onions, parsnips and beans in Tottenham, North London in July 1941.

Those who didn't have space for a bunker of their own took refuge in public shelters. Official bodies also needed safe spaces to meet and take shelter while the bombs fell.

Abandoned in 1932, Down Street station in Mayfair, pictured, was transformed into the Railway Executive Committee's bomb-proof bunker. During the height of the Blitz, British Prime Minister Winston Churchill took refuge in the tunnels of the station five times during the winter of 1940, after officials realised his official underground war rooms wouldn't survive a direct hit.

The British government's official bunker was completed in August 1939 and Winston Churchill visited for the first time in May 1940. The two-storey underground complex lay beneath the Treasury building in London's Whitehall. After a near miss later that year, it was discovered the refuge wouldn't survive a direct hit from a bomb, so it was reinforced with a layer of concrete up to 10 feet thick, known as 'the Slab'.

Churchill's War Cabinet met there a total of 115 times. However, despite having his very own office/bedroom – pictured – from where he made speeches to the nation, Churchill only slept there four or five times during the war, preferring to tough it out inside 10 Downing Street.

The RAF Headquarters Fighter Command was hidden beneath Bentley Priory in Middlesex, England. In the underground Operations Room at, members of the Women's Auxiliary Air Force (WAAF) are pictured here tracked incoming Nazi planes, as well as friendly aircraft positions, on the enormous plotting table.

Above, RAF officials coordinated squadron movements with the plotters, as well as displays showing weather conditions and the location of balloon defences.

Out in the field in Rouvres, France these members of the RAF's No. 73 Squadron were photographed taking shelter inside this underground duty office. They warm their hands over a tiny brazier as they await flying orders, while one of the team chats to the Operations Room via a field telephone. 

Note the structure of the shelter. It was built using the same curved corrugated iron design as Nissen huts and Anderson shelters.

Thousands of miles away on the island of Espiritu Santo in the South Pacific Ocean, these US Marines were photographed enjoying some downtime in April 1944. They can be seen playing badminton on a court marked out next to their Quonset hut.

Inspired by the British Nissen huts, the US forces designed the Quonset hut in 1941. Named after Quonset Point in Rhode Island, USA, where the shelters were first used, they were simpler to build than a Nissen hut, thanks to the lack of internal framework. 

Like Nissen huts and Anderson shelters, Quonset huts could be used as above-ground shelters or they could be sunk below ground. In fact, the adaptable structures were used in numerous ways, even after the war, and some remain to this day (but more on that later).

From 1942, Germany set about building the Atlantic Wall, a 2000-mile-long system of coastal defences that spanned six countries, from the top of Norway to the southern tip of France.

These German soldiers were photographed standing on top of a bunker in the Atlantic Wall in April 1943, during the German occupation of France.

Deep down in the Jersey War Tunnels lies the German Underground Hospital – also known as Hohlgangsanlage 8. The Second World War tunnels were constructed during the German occupation of Britain's Channel Islands and are over 3,280 feet long. They were built by more than 5,000 slave labourers from Russia, Poland, France and Spain, who carved the complex from the rock with gunpowder and hand tools.

Initially designed as an ammunition and artillery store, the bunker was quickly converted into a hospital. This image shows a sparse operating theatre. There were also wards, a medical supply room, a triage centre and a pharmacy.

Remnants of the Atlantic Wall are still scattered all over Europe, such as this concrete bunker on the seashore of Saint Ouen's Bay on Jersey in Britain's Channel Islands. 

Hidden in fields and among dunes, some of the bunkers have been adapted for other uses – by farmers, for example, for storing animal feed or farming equipment.

About 200 miles from Copenhagen lies one of the largest Second World War bunkers in the world. At 7,500 square feet, Tirpitz was one of 200 bunkers built by the Germans in Denmark during the war. The enormous concrete structure sits among the Jutland dunes, concealing a vault below. It was designed to include two towers housing naval guns, but it was abandoned, part-finished, when the Germans surrendered in May 1945.

Today, the extraordinary site hosts a museum.

The Cold War, which started in 1945 as the Second World War came to a close, brought a whole new interest in bunkers. Due to the heightened threat of nuclear attack, civilians and governments alike were looking for new ways to protect themselves. 

This black-and-white photo shows a man standing next to a personal bomb shelter in Glendale, California in 1951. 

Taken over a decade later in June 1962, this photo shows the sustained public interest in fallout shelters. 

Here, a crowd of shoppers gathers around a demonstration family-sized fallout shelter at Levittown Shopping Center in Pennsylvania at the height of the Cold War.

Many Cold War shelters would have had bunk beds, a camping stove and a chemical toilet, and been stocked with canned foods, bottled water and torches.

This cutaway display of a 1950s concrete masonry basement shelter boasts some additional luxuries, including an exercise bike, television and library.

This illustration of a pre-fabricated steel and concrete family bunker from the early 1960s brings to mind the corrugated metal bunkers of the First and Second World Wars.

Corrugated metal was a popular choice due to its innate strength. While it's comparatively easy to bend flat sheets of metal, corrugated metal won't bend across the lines of corrugation. This meant that once a sheet had been bent into the semi-circular shape required for building bunkers, it withstood further inward bending.

Meanwhile for the armed forces, the Quonset hut continued its usefulness following the Second World War and was put into use during the Korean War. 

This makeshift fortified church was made for the US Army's 40th Infantry, Division Replacement Company during the Korean War campaign in 1953. 

Quonset huts were used as bunkers and barracks during the Korean War, just as they had been during the Second World War.

These U.S. Marine fighter pilots of the 'Devil Cats' Squadron were pictured in October 1952 showing off their Quonset hut, which they had wallpapered with photos of almost 3,000 pin-ups. 

In December 1960, as the Cold War rumbled on, US Naval Construction Forces took a month to build a top secret bunker on Peanut Island in Palm Beach, Florida. It was made for US President John F. Kennedy, who was inaugurated the following month. 

The 1,500-square-foot facility was accessed via this door, reinforced with steel and concrete. Blast doors became a common site in government buildings and military installations during the Cold War.

The Quonset hut-style bunker was reached through a 40-foot-long corrugated metal tunnel and was covered with 12 feet of earth and layers of concrete and lead.

'The Detachment Hotel', as the installation was known, wouldn't have survived a direct hit, but it would have protected its occupants from nuclear fallout for up to 30 days. Inside, there were bunkbeds, a decontamination shower, radio, desk and the rocking chair favoured by the president. It didn't even include a functioning toilet.

Built in 1959, Canada's Diefenbunker consists of 100,000-square-feet of sprawling rooms and tunnels. Built in just 18 months, the enormous nuclear shelter lies 75 feet beneath Carp, Ottawa. 

The four-level complex is made from 5,000 tonnes of steel encased in 32,000 cubic yards of concrete. This 387-foot blast tunnel is sealed by doors weighing several tonnes.

Today, it serves as Canada's Cold War museum and the world's largest escape room.

Hidden in the depths of the Diefenbunker, this haunting statue celebrates Russian defector Igor Gouzenko. The Soviet cipher clerk had decoded secret messages in the Soviet Embassy in Ottawa before he defected with his wife and toddler in September 1945. 

Gouzenko has smuggled out over 100 top-secret documents, which he presented to Canada's Prime Minister William Lyon Mackenzie King. They proved Russian spy rings were operating in Canada, the USA and the UK, despite their alliance during the Second World War.

His efforts were said to have severely set back Russian spy efforts in North America for more than a decade.

Building began on this extraordinary nuclear facility in the wooded mountains of Chongqing, China in 1966. Known as 816 Nuclear Military Plant, the one-million-square-foot bunker was excavated by 60,000 engineers and features 18 main caves and more than 130 roads, tunnels and shafts.

Thought to be one of the world's largest man-made caves, it took 17 years to build. Note how tiny the group of visitors appear when compared with the bunker's soaring 262-foot high walls.

Built as a plant to process plutonium for an atomic bomb, the site was declassified in 2002 and opened to the public in 2010. Today, it remains an unusual tourist destination, its extraordinary structures accentuated by a modern lighting and sound system.

This space, which would have housed the nuclear reactor had the complex ever been fully finished, is washed in an eerie green light.

The Vietnam War – or Second Indochina War – ran from 1955 to 1975. Bunkers were used by both sides, but with particular effect by the Viet Cong, the communist regime of North Vietnam.

This bunker lies more than 29 feet beneath Building D67 in the UNESCO site of the Imperial Citadel of Thang Long, Hanoi. Known as the Central Military Commission bunker, it was used by communist revolutionary General Vo Nguyen Giap. Built in 1967, during intense bombing by the US, it's made up of four rooms and includes a meeting room, an office and two communications areas. 

Out in the field, Viet Cong fighters famously employed intricate systems of tunnels and bunkers to outfox American troops and escape intense aerial bombings. The most famous of these is the Cu Chi tunnels, a 130-mile long network of underground passageways and shelters built near Saigon, known today as Ho Chi Minh City.

Built over many years, the tunnels – and their hidden entrances and exits, pictured – were extraordinarily small, often too tiny for American GIs to squeeze into. 

The tunnels were rigged in places with explosive traps or pits of sharpened bamboo spikes, such as this one. The Viet Cong even found ingenious ways to confuse the American forces' sniffer dogs. Fighters would overpower their canine noses by placing chili peppers and spices next to the bunkers' air holes and smoke vents.

They also used pieces of American uniform, soap or aftershave to convince the dogs it was friendly territory, according to NBC News.

Thousands of underground passageways were built across Vietnam throughout the war. The Vinh Moc tunnels, pictured, were built for the inhabitants of a North Vietnamese coastal village that suffered from repeated American bombings.

More than 90 families moved into the three-storey underground complex, the tunnels of which cover over a mile.

As we can see in this picture, Viet Cong fighters and ordinary Vietnamese alike took shelter in chambers cut into the earth. The subterranean systems grew to include kitchens, hospitals, living quarters, munitions factories, bomb shelters and meeting rooms.

Some larger networks even had theatres and music halls to make underground life easier to bear.

These days, bunkers come in all shapes and sizes – and homeowners want them for numerous reasons. One of the most popular uses is as a storm shelter and many homes in weather-hit areas of the US include a safe space under the house or in the garden.

This one in Adairsville, Georgia likely saved pensioner Ken Jackson and his family when they took shelter inside it during the 'tornado outbreak' of 2013. He had built it almost 30 years before and used it nearly every time a storm rolled in.

Today there's a wide range of pre-fabricated, relatively low-cost bunkers available for those worried about everything from storms to nuclear attack. They start at just $19,000 (£15k).

In a time of global instability, pandemics, extreme weather events and a heightened nuclear threat, it's no wonder more and more people are prepping for the worst.

This city of bunkers near Edgemont, South Dakota has been labelled the 'largest survival community on earth.' Originally an army base, these 575 concrete and steel bunkers were built in 1942 but were decommissioned in the late 1960s. Now, they form a community of like-minded survivalists called Vivos xPoint. Currently, each bare bunker costs from around $55,000 (£44k).

Think this is the garden of a super-stylish, ultra-expensive home? If so, you're partially right. It's actually a room inside the world's most luxurious bunker – L'Heritage from Oppidum. 

The 10,760-square-foot design descends 49 feet below ground and is built to NATO-standard ballistic and blast protection levels. The bespoke bunker can be built almost anywhere in the world and it includes a concealed entrance, a decontamination chamber, biometric security, spacious rooms, a pool and even an art gallery – all for a cool $100 million (£80m).

Bunkers have certainly come a long way from the dark days of the First World War.

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