Among Oslo's attractions are the Vigeland sculptures in Frogner Park, a collection of more than 150 groups of bronze and granite sculptures depicting the cycle of human life. This monumental work was commissioned by the city of Oslo from Norway's best-known sculptor, Custav Vigeland. Across the city's harbor is the Bygd0y peninsula, with a number of museums. Perhaps the most famous is the Viking Ship Museum, where three 1,000-year-old Viking ships are preserved, together with many Viking artifacts. The ships look as if they could sail today. A large open-air folk museum is also found on Bygdoy, with groups of authentic old farm buildings, as well as a stave church from the 12th century. In the Polar Exploration Museum is the Fram, the ship used on expeditions by Norway's explorer-statesman Fridtjof Nansen, and by Roald Amundsen in 1911, when he became the first man to reach the South Pole. Next door is the Kon-Tiki Museum, which shows the famous balsa raft on which Thor Heyerdahl crossed the Pacific in 1947.