World heritage sites are cultural or natural landmarks or sites of "outstanding universal value" as designated by the United Nations Educational, Scientific and Cultural Organization (UNESCO). The sites are intended to be protected by their inclusion on the list and to be preserved for future generations. As of 2023, there are 1,157 World Heritage Sites in 167 countries, comprising 897 cultural, 218 natural, and 42 mixed properties. Examples of cultural sites include the Taj Mahal in India, the Great Wall of China, and the ancient city of Petra in Jordan. Examples of natural sites include the Grand Canyon in the United States, the Great Barrier Reef in Australia, and the Serengeti National Park in Tanzania.