Rising tensions between the United States and North Korea have got some Americans preparing for the worst. Bomb-shelter manufacturers, like Atlas Survival Shelters in Montebello, California, have reported a jump in sales of its anti-nuclear shelters, some of which can cost over $100,000 (S$137,000). Armed with facilities like escape tunnels, decontamination rooms, generators and water tanks, these underground structures are meant to be inhabitable for six months to a year.