These mounds in the landscape of South Dakota are formed by hundreds of concrete military bunkers, which are being repurposed to create the world's "largest survival shelter community".
Families and groups can lease the bunkers to be used as refuges in the wake of a catastrophic event, such as a nuclear war, a viral pandemic or an asteroid strike.
The peace of mind costs a $25,000 (around £20,500) downpayment, plus a 99-year land lease of $1,000 per year.

Vivos xPoint ? the self-proclaimed largest survival community on Earth ? is located in the Black Hills area of South Dakota, just south of the city of Edgemont.
The 575 hardened concrete bunkers on the site were originally built in 1942 as an army munitions depot known as Fort Igloo, which was eventually retired in 1967.
California-based survival company Vivos is now repurposing the massive complex, which is spread over approximately 18 square miles. The off-grid area is surrounded by a fence, and reached by road or a nearby municipal airport.
"It is strategically and centrally located in one of the safest areas of North America, at a high and dry altitude of [around] 3,800 feet," said Vivos, "with relatively mild weather, well inland from all large bodies of water; and [approximately] 100 miles from the nearest known military nuclear targets."

The earth-covered bunkers are reportedly built and fortified to withstand a 500,000-pound blast (seven bars of pressure).
They are separated from e...