Visby is a locality and the seat of Gotland Municipality in Gotland County, Sweden with 23,576 inhabitants, as of 2012. Visby is also the episcopal see for the Diocese of Visby. It is the only locality with historical city status on the island of Gotland. The Hanseatic city of Visby is arguably the best-preserved medieval city in Scandinavia and since 1995, it is on the UNESCO World Heritage Site list. Among the most notable historical remains are the long town wall that encircles the town center, and a number of church ruins. Visby is a popular vacation destination for Scandinavians during the summer and receives thousands of tourists every year. It is by far the most populated locality outside the Swedish mainland. Visby is also the only municipality seat of Sweden that is accessible only by boat and air traffic. The University of Gotland is in Visby, and since 1July 2013, it is a department of Uppsala University under the name Uppsala university–Campus Gotland.