In 2011, 1,087,000 tourists visited Ghana. Tourist arrivals to Ghana include South Americans, Asians, Europeans, and North Americans. The attractions and major tourist destinations of Ghana include a warm, tropical climate year-round, diverse wildlife, waterfalls such as Kintampo waterfalls and the largest waterfall in west Africa, Wli waterfalls, Ghana's coastal palm-lined sandy beaches, caves, mountains, rivers, and reservoirs and lakes such as Lake Bosumtwi and the largest man-made lake in the world by surface area, Lake Volta, dozens of forts and castles, World Heritage Sites, nature reserves and national parks. In addition to the beautiful natural reserves which serve as tourist sites, there are some castles in Ghana that serve as tourist sites and attract many tourists from all over the world. Some of the notable castles are Cape Coast Castle and the Elmina Castle all in the Central region of Ghana. Not only are the castles important for tourism, they also mark where blood was shed in the slave trade and preserve and promote the African heritage stolen and destroyed through the slave trade. As a result of this, the World Heritage Convention of UNESCO named Ghana's castles and forts as World Heritage Monuments.