Archeologists from the University of Pennsylvania at work in the Mayan ruins of Tikal (or Tik'al according to the modern Mayan orthography) is one of the largest archeological sites and urban centers of the pre-Columbian Maya civilization. It is located in the archeological region of the Pet矇n Basin in what is now northern Guatemala. Situated in the department of El Pet矇n, the site is part of Guatemala's Tikal National Park and in 1979 it was declared a UNESCO World Heritage Site. Tikal was the capital of a conquest state that became one of the most powerful kingdoms of the ancient Maya. The city dominated much of the Maya region politically, economically, and militarily. Tikal is the best understood of any of the large lowland Maya cities, with a long dynastic ruler list, the discovery of the tombs of many of the rulers on this list and the investigation of their monuments, temples and palaces.