There are twenty-five World Heritage Sites scattered across the United States. World Heritage Sites are the most important natural and cultural areas around the world ; these are the places that the United Nations, and the 167 countries it represents, have recognized as the most important contributions to the heritage of humanity . World Heritage Sites are premier visitor destinations, yet most people are not familiar with the World Heritage Site designation and many of the places included on the World Heritage List. A Guide to America's World Heritage Sites: The Heritage of Humanity describes these twenty-five sites, including why they are so important , the visitor attractions they feature, and logistical advice on how to visit, appreciate, and protect them.