Archaeologists have unearthed two ancient Maya cities hidden in thick vegetation in the Mexican jungle.
The cities were discovered in the southeastern part of the Mexican state of Campeche, in the heart of the Yucatan peninsula.
Expedition leader Ivan Sprajc, of the Research Center of the Slovenian Academy of Sciences and Arts and his team found the massive remains as they further explored the area around Chactun, a large Maya city discovered by the Slovenian archaeologist in 2013.
One of the newly discovered cities featured an extraordinary facade with an entrance representing the open jaws of an earth monster, 'Discovery News' reported.
The site was visited in the 1970s by American archaeologist Eric Von Euw, who documented the facade and other stone monuments with yet unpublished drawings.
However, the exact location of the city, referred to as Lagunita by Von Euw, remained lost.
Lagunita was identified only after the archaeologists compared the newly found facade and monuments with Von Euw's drawings.
The monster-mouth facade turned to be one of the best preserved examples of this type of doorways, which are common in the Late-Terminal Classic Rio Bec architectural style, in the nearby region to the south.
Researchers also found remains of a number of massive palace-like buildings arranged around four major plazas.
A ball court and a temple pyramid almost 65 ft high also stood in the city, while 10 stelae (tall sculpted stone shafts) and three altars (low circular stones) featured well-preserved reliefs and hieroglyphic inscriptions.
The other city unearthed by Sprajc was named Tamchen, which means "deep well" in Yucatec Maya.
More than 30 chultuns were found at the site. These are bottle-shaped underground chambers, largely intended for collecting rainwater.
Like in Lagunita, plazas were surrounded by large buildings. These include the remains of an acropolis supporting a courtyard with three temples on its sides.