National Treasures: The Art of Collecting

The great art collectors of the world reveal their most valuable treasures, starting with Nasser David Khalili, a collector of Islamic art who has amassed 35,000 pieces.

A trip to Venice opens up the opportunity to explore the late Francesco Carraro's remarkable collection of Venetian glass, which includes works by the acclaimed architect Carlo Scarpa.

David Lewis has amassed an enormous collection of works by the Old Masters, one of the largest in the UK. While he has loaned around 200 of them to national galleries, David offers a glimpse of some of his favourites kept in his home.

Prolific art collector Frank Cohen gives a tour of his warehouse, which houses works by Georg Baselitz, Frank Auerbach, LS Lowry, Edward Burra and Patrick Heron.

A look at six fascinating watches from an extensive collection spanning 300 years of watchmaking, including one timepiece made in London the year before the Great Fire ravaged the capital.

The art collection and jewels of Attilio Codognato in Venice, who built on his family heritage to make pieces for notable clientele from actress Elizabeth Taylor to the Duchess of Windsor.