A joint Slovenian-Mexican archeological team has discovered an undisturbed Mayan city in a remote area of Campeche, Mexico. Located deep within the jungles of the Calakmul Biosphere Reserve, the city—which the researchers have named “Minanbé,” a Maya Yucatec phrase meaning “there is no road”—had been hidden by vegetation for over a thousand years.

The site features a 43-foot-high pyramid temple (about the height of a four-story apartment building), and 14 carved altars and stelae, according to Mexico’s National Institute of Anthropology and History (INAH), which authorized the expedition. The discovery is the culmination of lead archaeologist Ivan Šprajc’s three-decade-long exploration of the Central Maya Lowlands, home to between 9 and 11 million people during the Maya civilization’s Late Classic period (600–900 CE).