According to a 12 year old article from theguardian.com...

They are known for purchasing "awkward" works, such as video installations, that many other private collectors will not consider. "It's easy to store them, but difficult to display them," says Podesta. To get round the problem, he and his wife have excavated a huge subterranean vault beneath their house outside Washington - a white space 5m square and 4m high in which it will be possible to show "very complicated video pieces" on all four walls.

https://www.theguardian.com/culture/2004/apr/20/usa.world

archive: http://archive.is/yMJeG