For billionaires like Peter Thiel, plan B is another country. Here's where they're lining up passports or second homes.

The number of billionaires like Peter Thiel investing in geographic backup plans — be they passports or residence programs — is on the rise.Bloomberg/Getty ImagesWhether prepping for doomsday or political backlash, US billionaires are increasingly seeking geographic backup plans.Peter Thiel's relocation to Argentina is the latest example.Here are five popular passports that the ultrarich are adding to their trophy cases.Forget breaking glass. In case of an emergency, billionaires wil