Deep in the basement of the Tehran Museum of Contemporary Art, behind a door that opens with a spoked wheel like a bank vault, are some 2,000 paintings by artists such as Francis Bacon, René Magritte, Claude Monet and Paul Gauguin. Iranian curators say the collection is estimated to be worth $5 billion, but only a select group of people have seen it since the 1979 revolution. A few days after I arrived in Tehran in February, I was given a rare opportunity: a private underground tour of the former shah’s art collection, one of the largest in the Middle East, housed in a building that the shah’s wife, Farah Pahlavi, erected in the 1970s. There have been occasional limited exhibits, but most of the art has been in storage for decades. A few lucky visitors are now allowed to view the collection, and there are negotiations underway for at least part of it to travel to Germany and the U.S. in 2016.