Hydra is perhaps the most singular of the Greek islands — no cars, no motorbikes, and no scooters are allowed anywhere on the island. Everything moves by donkey, foot, or boat. The harbour town is one of the most beautiful in the Aegean: stone mansions built by 18th-century sea captains climb the hillsides above a perfect natural harbour, and the waterfront is lined with cafes and restaurants. Artists and writers have been coming here since the 1950s; Leonard Cohen lived here for years and wrote some of his best early work on the island.
Two hours from Athens by hydrofoil, Hydra is very accessible and very popular in summer — but the carless atmosphere keeps it from feeling hectic. The swimming is good off the rocks around the harbour and at Vlychos, the small cove west of town, and the island has enough walking trails through scrubby hillsides — most notably the climb to the Monastery of Profitis Ilias — to keep you occupied for a few days.