Vasa (or Wasa) is a Swedish warship built 1626-1628. The ship foundered and sank after sailing less than a nautical mile (ca 2 km) into its maiden voyage on 10 August 1628. It fell into obscurity after most of its valuable bronze cannons were salvaged in the 17th century. After it was located again in the late 1950s in a busy shipping lane just outside the Stockholm harbor, it was salvaged with a largely intact hull in 1961. It was housed in a temporary museum called Wasavarvet ("The Wasa Shipyard") until 1987 and then moved to the Vasa Museum in Stockholm. The ship is one of Sweden's most popular tourist attractions and has been seen by over 29 million visitors since 1961. Vasa has since its recovery become a widely recognized symbol of the Swedish "great power period". It is today also a de facto standard in the media and among Swedes for evaluating the historical importance of shipwrecks.

Vasa was built top-heavy and had insufficient ballast. Despite an obvious lack of stability in port, it was allowed to set sail and foundered only a few minutes after it first encountered a wind stronger than a breeze. The impulsive move to set sail was the result of a combination of factors: Swedish king Gustavus Adolphus, who was leading the army on the continent on the date of its maiden voyage, was impatient to see it join the Baltic fleet in the Thirty Years' War; at the same time, the king's subordinates lacked the political courage to discuss the ship's structural problems frankly or to have the maiden voyage postponed. An inquiry was organized by the Swedish privy council to find personal responsibility for the disaster, but in the end no one was punished for the fiasco.