Tikal National Park encompasses 575 square kilometres of jungle and thousands of ruined structures. The central part of the ancient city alone contains 3,000 buildings and covers about 16 square kilometers. Tikal is also part of the one-million-hectare Maya Biosphere Reserve created in 1990 to protect the dense forests of the Peten, which started to disappear at an alarming rate due to population pressures, illegal logging and slash-and-burn agricultural practices. Archeologists estimate that the Maya settled in the area now known as Tikal in about 900 BC.