Mayan city in Mexico
Calakmul, one of the most important cities of Mayan civillization is Mexico's first "mixed natural and cultural" World Heritage Site according to UNESCO.Reuters

Archaeologists have reportedly found two ancient Mayan cities hidden in the Yucatan jungle of south-eastern Mexico.

Ivan Sprajc, associate professor at the Research Center of the Slovenian Academy of Sciences and Arts, told Reuters that his team found the ancient Mayan cities of Lagunita and Tamchen on the Yucatan peninsula in April by examining aerial photographs of the region.

In the 1970s, Eric Von Euw, an American explorer had ventured into an unexplored forest at the base of Mexico's Yucatan peninsula near the border of Guatemala.

Spanning over a region of 2,800 square miles, the Calakmul biosphere reserve is an expanse of trees and rivers. Von Euw had drawn images of an "extraordinary facade with an entrance representing open jaws of the earth monster" that was never published. The site and the city that held it, which came to be known as "Lagunita", became more of a myth over time.

Now, over four decades later, another explorer ventured into the Yucatan jungle, with the same desire many before him had: locate the "open jaws of the earth monster".

After a two-month expedition, Sprajc has returned with not just drawings, but photographs, of not just Lagunita, but another previously unknown city, that he named "Tamchen".

Sprajc said the two cities were at their zenith during the Late and Terminal Classic periods (600-1000 AD). Each site housed palace-like buildings, pyramids and plazas, of which one pyramid was almost 20 metres (65 feet) high.

Though Spranjc's team trudged into the forests with machetes, trucks and tortillas, a bird's eye view and Von Euw's drawings for reference, is what helped to discover Lagunita.

"In the jungle you can be as little as 600 feet from a large site and do not even suspect it might be there; small mounds are all over the place, but they give you no idea about where an urban center might be," Sprajc told Discovery News.

Before that discovery, almost nothing was known about the archaeological treasures contained in the forests, which boast architecture dating back to 600 AD. In fact, the "monster-mouth facade", which represents "the gaping maws of the earth and fertility deity", turned to be one of the best-preserved examples of such doorways and marked one of the main entrances to the center of the city.

"The entrance apparently symbolizes the entrance to a cave and to the underworld ... Someone entering through this doorway would have entered sacred precincts," Sprajc told. The team has not yet excavated the sites and Sparjc believes that the cities were probably much larger than what they have been able to map so far.

Last summer, Sprajc had discovered another ancient Mayan city, Chactun, 10 km (6 miles) north of Lagunita and 6 km (4 miles) northwest of Tamchen.