Located in the southern portion of the Yucatan Peninsula, Calakmul sits within an ecological preserve of 331,397 hectares, surrounded by a buffer zone of an additional 391,788 hectares. Together, this vast territory makes up the Calakmul Biosphere Reserve. Since the decline of Calakmul and other nearby Mayan cities around 900 C.E., this area has remained undeveloped. It is, therefore, easy to understand why the site remained undiscovered by outsiders until 1931. At that time, Cyrus Longworth Lundell (1907-1994), a native of Austin, Texas, and one-time student at Southern Methodist University in Dallas, Texas, traveled to Campeche, Mexico, as a representative of the Tropical Plant Foundation in Washington, D.C., and the American chewing gun industry. While searching for chicle (natural gum) in an uncharted area of Campeche, he learned about the ruins of a lost Mayan city from locals, which he named Calakmul, “the city of two adjacent mounds.” This proved to be only the first of 16 ancient cities and other Mayan sites that he discovered. In 1932, Lundell informed Sylvanus Morley, then working at Chichen Itza, about the Calakmul site and his count of roughly sixty stelae there. Morely then organized the first Carnegie Institution of Washington expedition to the site in April 1932. This was followed by three additional surveys, ending in 1938, which resulted in the mapping of the city’s central area and the recording of 103 stelae.

Although the Calakmul Biosphere Reserve is largely uninhabited today, from 500 B.C.E. to roughly 1,000 C.E., it was home to a number of Mayan urban developments. The largest settlement was the city of Calakmul itself, which served as the seat of the Snake Kingdom -- called Kaan -- one of the most powerful Maya dynasties during the Late Classic Period. Represented by a snake head glyph, Calakmul fought with both Tikal and Palenque for regional dominance. With more than 6,200 buildings in a core area of 30 square kilometers (11.5 square miles), it was more densely settled than Tikal and had more stelae (115 to 130) than any other Maya city. Unfortunately, the stelae at the site are so badly eroded that archaeologists and epigraphers are having to piece together much of Calakmul’s history from records left in other areas. For example, the site of Dzibanche, about 200 kilometers to the northeast, provides an early reference to Calakmul. There, Yaknoom Ch’een, the Snake King, is shown receiving captives. Unfortunately, there are no references to a king at Calakmul itself until the seventh century. Even the painted vessels that archaeologists have found describing Calakmul’s 19 kings have proved problematic, since they don’t match the record presented in the stone stelae that can be read.
What we do know about Calakmul is that it began to appear in the glyphic record at Yaxchilan (537 C.E.) and Naranjo (546 C.E.). By 561, the King of Calakmul, Sky Witness, turned a large city, Caracol, against its ally and protector, the powerful state of Tikal. By 562, Calakmul and Caracol defeated Tikal, and Sky Witness attended the execution of Tikal king’s Wak Chan K’awill. This began a “hiatus” in Tikal’s record, which lasted 130 years.
Some Mayanists have suggested that Calakmul targeted Tikal because of that state’s link to Teotihuacan, the largest pre-Columbian city every built in the Americas just north of modern day Mexico City. The imagery of Teotihuacan had spread throughout the Peten region by the sixth century and existed everywhere but Calakmul. Both Naranjo and Caracol stopped displaying Teotihuacan symbolism when they shifted to Calakmul’s side. In fact, after defeating Tikal, Calakmul allowed the city to keep its kings, but the state was forbidden from displaying Teotihuacan’s imagery. So, perhaps Calakmul wanted the Maya region to be totally independent from Teotihuacan’s sway. Whatever the case, Calakmul began to decline during the eighth century CE.