 "Bitcoin")
Behind the guards, the blast doors and down corridors of reinforced concrete, sit the encrypted computer servers -- connected to nothing -- that hold keys to a vast digital fortune.
Argentine entrepreneur Wences Casares has spent the past several years persuading Silicon Valley millionaires and billionaires that Bitcoin is the global currency of the future, that they need to buy some, and that he’s the man to safeguard it. His startup, Xapo, has built a network of underground vaults on five continents, including one in a decommissioned Swiss military bunker.
In the rarefied world of wealth management, Xapo is known for a
