The archeology of the area around the city is little studied, in part because the main archeological sites are difficult to access and the climate of the southern Isthmus makes excavation work difficult. Much of the area's early cultural interactions are only speculated about but it is known there was contact with Teotihuacan, Tula, Monte Alban and later, Tenochtitlan. The Tehuantepec area in the very early Pre Classic period was on the periphery of the zone where the Olmecs had influence as is noted by artifacts. The area's initial importance was not as a center of a dominion but rather as part of a trade route which connected Central America with what is now central Mexico. Through its trade routes passed manta rays, jade, other precious stones, shells, sponges, gold, amber, salt, feathers, furs, cotton, spices, honey and cocoa. The main control point for this trade route in this area was mostly likely Lass Gui’e’e, according to recent excavations. This site has a history of at least 3500 years with Olmec and Chiapas-origin figures found in its oldest sections. This and the abundance of marine shells indicate that this site in the Cañada de Tehuantepec was the main axis of communication between the Oaxacan highlands the Isthmus of Tehuantepec and into Guatemala since early in Mesoamerican history.