 The riverine drainage system of the Pasión and its tributaries covers an area of over and forms a watershed for a substantial portion of the present-day Guatemalan department of Petén's western half.The Pasión river basin is recognized as an archaeological region or zone, and contains a number of archaeological sites of the pre-Columbian Maya civilization, which to an extent shared some commonalities in Maya architectural style, political history and glyphic conventions.Maya ceremonial and urban centers located within the region include Dos Pilas, Tamarindito, Altar de Sacrificios, Aguateca, Seibal and Machaquila.