Bulverket

Bulverket
Native name Swedish: Bulverket
Bålverket, Tingstäde Bulverk
Geologist Lennart von Post recovering part of the Bulverket in 1927.
Type	Lake fortification
Location	Lake Tingstäde, Gotland, Sweden
Nearest city	Tingstäde
Coordinates	57°43′40″N 18°37′43″E / 57.72778°N 18.62861°E / 57.72778; 18.62861Coordinates: 57°43′40″N 18°37′43″E / 57.72778°N 18.62861°E / 57.72778; 18.62861
Area	40,000 square metres (430,000 sq ft)
Elevation	40 m (130 ft)
Original use	Unknown
Architectural style(s)	Viking wooden construction

The Bulverket is the remnants of a large wooden fortification or bulwark at Lake Tingstäde on the island of Gotland, Sweden. When built, it consisted of a platform with houses surrounded by a double palisade with the entire construction around 250 m (820 ft) in diameter.

According to a 1989 archeological survey, the structure was built in the 1130s and may have been used for less than a century. Although its original purpose is unknown, theories suggest it was either used as a shelter during the turbulent times on Gotland at the end of the Viking Age or that it was the site of a last stand.

Among the archeological finds at the Bulverket are the remains of three boats. One of these served as a model for the reconstruction of a Viking boat, the Krampmacken, in 1980. The Krampmacken has subsequently made several journeys following old Viking waterways through Eastern Europe.

The name Bulverket originates from the old Swedish words bul, meaning "log", and verk which refers to something "built". It is related to the English word "bulwark", a form of fortification, as well as the Dutch bolwerk with the same meaning and the Swedish bålverk.

It is likely that the Bulverket has been known to the local people for centuries, as thousands of logs can be seen through the water on a calm day, and it is also considered the best place for perch fishing on the lake. However, there is no oral lore regarding its construction, purpose, or fate. All that remains is a saying used in the northern part of Gotland that concerns large amounts of smoke: "There is smoke just like when Lake Tingstäde burned".(Swedish: Det ryker som när Tingstäde träsk brann.)

The Bulverket was first mentioned in written sources in 1868, when Swedish archeologist Oscar Montelius wrote that naturalist and teacher Dr. Lindström discovered poles in Lake Tingstäde in 1866.

One of the recommended ways of seeing the Bulverket is during the winter, when the ice is smooth and clear and the lake is used for tour skating.