The money came from the unglamorous world of mining and minerals. The passion for collecting, striking in many of the richest European and American Jewish families, came from somewhere deeper.
In the late 1930s, as war approached, Peggy Guggenheim was said to be buying a work of art a day. In a few years she had spent $40,000 on the the project and acquired works by Constantin Brancusi, Alberto Giacometti and Max Ernst - to whom she was briefly married - which are now priceless.
The Guggenheims often bought cutting-edge art that would take years to become fashionable. They used advisers but also made purchases based on their own instincts.
Solomon Guggenheim's first New York gallery, the Museum of Non-Objective Painting, began life in 1937 in a former car showroom. In 1945, Frank Lloyd Wright unveiled his sensational model of a permanent home for the collection. Many doubted his spiral "temple of spirit" could be built. When it was completed in 1959 the building drew far larger crowds than the collection, just as the gleaming metal curves of Frank Gehry's Bilbao Guggenheim did when it opened in 1997.
Peggy Guggenheim's desire to create something equally startling was confounded by the second world war. She ran a string of temporary galleries, but failed to find a suitable permanent site in London or Paris. Eventually her collection found a haphazard base in her home in Venice.
The gallery has one of the most glamorous sites in the city, with a magnificent pillared gate on the Grand Canal left over from a Renaissance palazzo.
The new gallery would be the third Guggenheim in New York. As well as the Frank Lloyd Wright building, a smaller gallery in SoHo was opened in 1992.
In 1979, on her death, the Peggy Guggenheim Collection became part of the Guggenheim Foundation. Then in 1997 two new Guggenheims appeared. The Berlin Guggenheim, specialising in German collections reflecting the family's homeland, was developed in partnership with Deutsche Bank, and occupies the ground floor of its headquarters close to the Brandenburg Gate.
In the same year the Bilbao Guggenheim was launched and transformed the economy of the rundown post-industrial city at a stroke.
