The walled and cobbled medieval port of Visby is a living relic: more than 40 proud towers and the ruins of great churches attest to Visby's former Hanseatic glories. The contemporary ruins of Drotten, St Nicolai, St Lars and St Carin are all within the town walls and contrast with the old but sound cathedral of St Maria. Gotlands Fornsal is the historical museum with a fine collection of the Gotland picture stones of the pre-Viking period. During the second week of August, costumes and re-enactments commemorate medieval week. Visby is on the island of Gotland, which is serviced by flights from Stockholm and ferries from a number of mainland cities.