Visby is a locality and the seat of Gotland Municipality in Gotland County, on the island of Gotland, Sweden with 24,330 inhabitants, as of 2017. Visby is also the episcopal see for the Diocese of Visby. The Hanseatic city of Visby is arguably the best-preserved medieval city in Scandinavia and since 1995, it has been on the UNESCO World Heritage site list. Among the most notable historical remains are the 3.4 km (2.1 mi) long town wall that encircles the town center, and a number of church ruins.