Located on the Aegean Sea, Hydra Island is one of Greece's most beautiful. With a population of about 3,000 and no automobiles allowed, the popular tourist destination is only a day trip from Athens. In the 15th century, a powerful merchant fleet was constructed, enabling prosperity through transit trade. The fleet joined the fight for Greek independence, achieving victory in 1827. But Hydra's transit trade suffered so vehicle roads were not built. Mules are the principal mode of transportation.