Visby is a town located on the Swedish island of Gotland in the Baltic Sea. It is the largest town on Gotland and is also the island's main center of commerce, tourism, and culture. Visby is known for its well-preserved medieval town center, which is surrounded by a 3.4 kilometer-long wall.

The town was founded in the 10th century as a Viking settlement, and was later an important center for the Hanseatic League, a powerful trade alliance that dominated the Baltic Sea region during the Middle Ages. During this time, Visby grew wealthy and prosperous, and its walls and towers were built to protect the town's riches.

Today, visitors to Visby can explore the town's well-preserved medieval streets and buildings, which include a number of historic churches, such as St. Mary's Cathedral and St. Nicholas' Church. The town also has several museums, including the Gotland Museum, which houses exhibitions on the island's history and culture.