A site plan for the underground shelter for RVs near Atchison, Kan.

There are only 1,000 parking spaces available, so you may want to get in on this quick: A California developer is turning a vast area of underground caverns into a post-apocalyptic shelter.

The Atchison, Kan., caves cover 45 acres and have room for 1,000 RVs; customers will be charged $1,000 for each linear foot of RV space and $1,500 for each person’s food, according to newsier.com.

The caverns are between 100 and 150 feet underground and will boast doors that can handle a one-megaton nuclear explosion as few as 10 miles away. Sales haven’t begun yet because developer Robert Vicino is waiting for a “critical mass” of reservations.

Vicino says the former Army storage facility, some 50 miles northwest of Kansas City, Mo., will be the world’s biggest private underground survival shelter, the AP reports. “I do believe I am on a mission and doing a spiritual thing,” he says.

The caverns were originally dug in the 1880s as part of limestone mining work and later used as an Army storage facility. Investor Coby Cullins won the property at auction for $510,000 in April. Soon after, Vicino arranged to buy 75% of it for what will become the Vivos Survival Shelter and Resort, adding further intrigue to the town of Atchison—the supposedly haunted birthplace of Amelia Earhart. (Vivos runs a range of survival shelters, from the plush to the economical.)