Imatrankoski ("The Imatra Rapid") is a rapid on the Vuoksi River in Imatra, Finland. It has been a famous tourist attraction since the late 1700s. Imatrankoski is also one of the National landscapes of Finland. Since 1929 the rapid has been blocked by a dam as the Imatra hydroelectric plant began operation. Today, the dam is opened daily between June and August, as well as on Christmas Day and New Year's Eve.
The Vuoksi River and Imatrankoski were born about 5,000 BP as the waters of the Saimaa Lake penetrated the Salpausselkä ridge due to post-glacial rebound, forming a river flowing into the Lake Ladoga.
Tourism in Imatrankoski is considered begun in 1772 as the Empress of Russia Catherine the Great visited the site. The Kruununpuisto Park, the oldest nature park in Finland, was established in 1842 by the Emperor Nicholas I. At the end of 19th century, Imatrankoski was one of the best known nature attractions in Europe. The hotel Valtionhotelli was finally opened in 1903.
