Step through the archway of Galle Fort and time does something strange - it slows down, shuffles its feet, and starts walking at a Dutch colonial pace. You are inside one of the best-preserved fortified cities in Asia, and it is still very much alive. Perched on a rocky headland on Sri Lanka's southwest coast, where three sides of the promontory face the open Indian Ocean, Galle Fort is both a living neighbourhood and one of the world's most remarkable historical monuments. It has been a UNESCO World Heritage Site since 1988 - and once you arrive, it's easy to understand why.