People outside shelter (Credit: Getty Images)
In World War One, aerial bombing suddenly meant civilians had to find shelter.
Children in Blitz bomb shelter (Credit: Getty Images)
The German bombing of Britain in World War Two forced many to build simple shelters in their homes. ‘Anderson shelters’ were improvised bunkers for those without a garden or cellar.
People building shelter (Credit: Getty Images)
With the advent of nuclear weapons, the need for shelters became greater. Because of the dangers of radiation, people would have to stay below ground for long amounts of time until radiation levels lessened.
Family in shelter with food (Credit: Alamy)
Nuclear shelters need to be airtight to keep out radioactive fallout, and have enough room to keep weeks – or possibly even months of supplies.
Men with shelter generator (Credit: Getty Images)
Some of the larger government shelters had everything needed to keep inhabitants in touch with the world above. Generators within the shelter would keep heating, power and air conditioning functioning.
Room in US shelter (Credit: Getty Images)
In the event of nuclear war, senior figures from the US government would descend underground.
This bunker in White Sulphur Springs, Virginia, is designed to house senior government figures, and is now a tourist attraction.
Soviet nuclear shelter (Credit: Getty Images)
The Soviet Union too built a network of bunkers to protect its leadership, one of which housed 1,500 people 60m (197ft) underground.
In operation until 1985, it was used to keep radio and telephone exchanges safe in the advent of a nuclear attack.
Polish fallout shelter (Credit: EPA)
As the Cold War simmered, many other European countries also built shelters, like this one in Poland, which was part of a Soviet nuclear weapons base.
Shelter radio unit (Credit: Getty Images)
In the UK, some underground bunkers even had office-style meeting rooms and radio equipment that could broadcast on BBC radio frequencies.
Man in gas mask (Credit: Alamy)
Since the fall of the Berlin Wall, the threat of nuclear confrontation has lessened – and the nuclear fallout bunker business has also appeared to have faded.
Now, shelters – like this one in a British house recently offered for sale – are seen as more of a curio than a must-have.
Shelter salesman on bed (Credit: EPA)
But for a select few, a blast-and-radiation-proof shelter is a safeguard worth investing in.
Shelter builders such as Ron Hubbard, based in California, have reported a spike in interest amid tensions with North Korea.