The island is only four miles (6km) wide and seven miles (11km) long. Away from the resort areas along the south and east coast it is relatively undeveloped with shady woods, olive and walnut groves and quiet beaches that can only be accessed by boat. The seafront in Skiathos Town is lined with local tavernas, cafйs and some excellent seafood restaurants that look over the lively marina. From here boat trips leave to take tourists around the island to swim in the sparkling blue-green waters and see the sights, which include a ruined Venetian fortress dating from 1207, and the deserted 14th-century town of Kastro. The most famous beach on the island, and perhaps Greece, is Koukounaries, a one-mile (2km) long strip of fine golden sand and crystal clear water set in front of a thick pine forest. It attracts many visitors especially during July and August and offers all sorts of watersports facilities.