Built as an impregnable fortress in the 17th century AD, the Nya Älvsborg Fortress is located on a small island at the mouth of the Göta Älv River, and is one of the prominent historical and tourist places in Gothenburg. Accessible by boat, the castle is greeted by a group of people dressed in 17th-century costumes who take them on a historical tour of the passages, cannons, forts and dungeons.