Príncipe is the second largest island in the archipelago and reached by a 30-minute flight north from São Tomé. Smaller Príncipe is home to a mere 6,000 islanders. Just 19km long, its north coast is notched with castaway shores that include the perfectly curved Banana Beach, which is so definitively palm-fringed and golden it once starred in a Bacardi ad. In 2012 Príncipe was declared a UNESCO Biosphere Reserve on account of its rich biodiversity, and this is a choice spot to look for humpback whales and nesting turtles. Three years ago, its principal hotel, Bom Bom Island Resort, was bought by Mark Shuttleworth, the South African philanthropist and billionaire who travelled into outer space in 2002. Now he is investing in both islands to help create a model eco-tourist destination.