A 64-gun wooden warship, just over 45 metres (147 ft) in length, built at Stockholm to the order of the Swedish king Gustavus Adolphus, and the only surviving example of the complete hull of a 17th-century warship. On 10 August 1628 she sank in Stockholm harbour on her maiden voyage after a strong gust of wind heeled her over so far that she was flooded through her open gunports. Attempts to raise her later that century failed, but she was rediscovered in 1956. In April 1961 a complicated salvage operation brought the almost complete wooden hull to the surface from a depth of 33 metres (110 ft). Though all her iron nails and bolts had disintegrated, the hull had remained almost intact because it was held together by a large number of treenails. About 25,000 objects, including carvings, textiles, leather, coins, equipment, and a number of skeletons were recovered, as well as parts of the ship. She was housed in a temporary museum and over a number of years her timbers were treated with polyethylene glycol to preserve them, and she was eventually fully restored. In 1990 she was housed in a new Vasa museum in Stockholm where the temperature is controlled. See also marine and underwater archaeology; shipwrecks.