The Facts

• A doctoral candidate at the Northern Arizona University has accidentally discovered a long-lost Mayan city — now named Valeriana by archaeologists — in Mexico. The city, now buried under the forest 50 sq. miles off Campeche, is estimated to have flourished between 750 and 850AD.

• Anthropologist Luke Auld-Thomas stumbled onto the find when he revisited a 2013 survey done for a forest monitoring project using the Lidar remote sensing technology to generate 3D images of the site. Researchers now suggest there may be many more such lost cities to be found.

• Data collected suggest Valeriana was a populous city with at least 6,764 built up structures and an aggregate settlement density of 55.3 structures per sq km. The findings published Tuesday in the journal Antiquity show that it was around 1.5 times the area of Washington DC.