Calakmul is a Maya archaeological site in the Mexican state of Campeche, deep in the jungles of the greater Petén Basin region. It is 35 kilometres from the Guatemalan border. Calakmul was one of the largest and most powerful ancient cities ever uncovered in the Maya lowlands. Calakmul is a modern name; in ancient times the city core was known as Ox Te' Tuun. Calakmul was a major Maya power within the northern Peten region of the Yucatan of southern Mexico. Calakmul administered a large domain marked by the extensive distribution of their emblem glyph of the snake head sign, to be read "Kaan". Calakmul was the seat of what has been dubbed the Kingdom of the Snake or Snake Kingdom. This Snake Kingdom reigned during most of the Classic period. Calakmul itself is estimated to have had a population of 50,000 people and had governance, at times, over places as far away as 150 kilometers. There are 6,750 ancient structures identified at Calakmul the largest of which is the great pyramid at the site. Structure 2 is over 45 metres high, making it one of the tallest of the Maya pyramids. Four tombs have been located within the pyramid. Like many temples or pyramids within Mesoamerica the pyramid at Calakmul increased in size by building upon the existing temple to reach its current size. The size of the central monumental architecture is approximately 2 square kilometres and the whole of the site, mostly covered with dense residential structures, is about 20 square kilometres.