Aerie – which will reportedly cost around $300 million (£231m) to build – will be a secure structure packed with protective features, extraordinary experiences and seriously opulent extras. Each facility is a NBCET sanctuary, which means it protects against nuclear, biological, chemical, electromagnetic pulse and technological attack.

And there won't be just one Aerie. Eventually, there'll be an exclusive network of them, with one in each US state and a total of 1,050 worldwide, according to founder Al Corbi, whose company SAFE (Strategically Armored & Fortified Environments) has provided security to the world's wealthiest since 1971.

Tour the billionaire bunker Aerie, the ultimate underground survival retreat