Virgin Atlantic has sponsored this article. All editorial views are those of Lonely Planet alone and reflect our view of editorial independence and impartiality. It is 58 million years old and 346km long. It has 80 islands, 45 locks and more than 200 rowing clubs. It’s crossed by 104 bridges and is home to 100 species of fish; briefly, in January 2006, one lost bottle-nosed whale joined the throng.