or the church of Our Lord () in revenge for the plundering of their town. In 1533–34, the new Danish governor, , demolished St. John's and St. Peter's churches to improve the defence of his castle Visborgs slott. St. Mary's Cathedral remained the last functional church and became the new city parish. Gotland was again taken into Sweden's possession in 1645, by the Treaty of Brömsebro, after 300 years of Danish rule. The city developed slowly as things were left as they were. In the mid 18th century, after a plague had reduced Visby's population, some attempts were made by Swedish government officials to improve living standards, but little was accomplished. Not until the early 19th century did Visby once again attract commerce and a harbour industry. At the same time – 1808 – Gotland was conquered by Russia, but was peacefully taken back by the Swedes after only a couple of months. Geography Visby is the name of the locality, or town, as well as the name of the larger area surrounding it, Visby socken. In 1936, the socken was incorporated within the newly formed Visby stad (Visby city), the only locality with historical city status on Gotland. Visby socken comprises the same area as the administrative Visby District, established on 1January 2016. , Visby Cathedral, Visborg Church and Terra Nova Church in Visby belong to Visby Cathedral parish (Visby Domkyrkoförsamling). Visby is also the only municipality seat of Sweden that is accessible from the mainland only by boat and air traffic. Visby is situated on the central west coast of Gotland, on the rather steep slopes of limestone cliffs surrounding the first natural harbor. The town has evolved around the medieval harbor that now constitutes the Almedalen park. Long streets run parallel with the old shoreline with shorter alleys at a straight angle from these, lead from the harbor and up the slope up to the eastern higher part of town known as Klinten. The old, original part of Visby is more or less enclosed by the city wall to the north, east and south, with the old harbor and the Baltic Sea in the west. The more modern parts of the town expand mostly east and inland from the wall. Along the shore south of the wall is the modern harbor with its ferry terminals and further south is a green recreational area called Södra Hällarna. Just