I am swimming 30 kilometres in the Norweigan sea, within the Arctic Circle, to raise money to finish our recreation of the Ark of John Tradescant, the 17th-century gardener and collector whose life was the inspiration for the Garden Museum. We want to display two specimens of natural history which were once in his Museum: a Nile crocodile, and a whale. The Natural History Museum has found two splendid ‘surrogate’ specimens which will startle and intrigue visitors, just as they did in Tradescant’s time. The whale is really exciting: a skeleton of a right whale recently discovered in the Thames shore, and which has been dated to Tradescant’s time. Having swum the Hellespont, Strait of Gibraltar, and the Thames from Oxford to London to raise money to enhance our Museum, this time I'm retracing part of Tradescant’s journey to Russia in 1618, when he watched whales from the deck. The cost? £75,000 for conservation and display cases. The challenge? Not the distance but the cold! I HATE cold water, and it will be really cold!