The first archaeological expedition to a lost ancient city in eastern Honduras has returned with exciting new discoveries. The explorers have come back with a treasure trove of images, yet have barely scratched the surface of what the city has to reveal about a culture so forgotten it lacks even a name.

The discoveries include 52 objects that were half-buried in the ground in what seems to have been an act of sacrifice before a temple. Among these is a carved head thought to represent a combination of human and jaguar features. Many more items are presumed to be buried deeper within the soil.

The extraordinary mathematics and architecture of the Mayan culture of Central America have achieved considerable fame worldwide. However, shortly after their classic civilization collapsed, something of possibly equal significance was going on to the east of the Mayans that has remained almost entirely unknown until now.

While Professor Christopher Fisher of Colorado State University had heard rumors of what was called the “White City” or the “City of the Monkey God,” the rainforest had reclaimed the city to such an extent that its location was unknown, at least to outsiders, until 2012 when airborne LiDAR mapping revealed the city's likely presence. Those images showed signs of buildings stretching along a great swathe of riverbank.

When Fischer and his colleagues entered the lost city, they found that its isolation is so great that it has escaped looting in the 600 or so years since it was abandoned. “This is clearly the most undisturbed rain forest in Central America,” ethnobotanist Dr. Mark Plotkin of the Amazon Conservation Team told National Geographic, whose photographer accompanied the team.

A lost city might sound like something from an Indiana Jones film, but three years ago Fisher documented a Purépecha city in Mexico, which hosted a civilization that rivaled the Aztecs. The archaeological team believe that the most recent find is one of several cities hidden in the forest that have collectively given rise to the White City legends of the La Mosquitia region of Honduras.

The civilization that built the city is believed to have flourished from A.D. 1000 to 1400. The cause of their demise is unknown, and almost all we can surmise about them comes from the findings of this dig and comparisons with neighboring cultures of the same era.

One the most memorable objects uncovered is "a were-jaguar" that "seems to be wearing a helmet,” Fisher told National Geographic, and which might depict a shaman in a spirit state. Other findings at the site include vessels carved with detailed renderings of animals and human-animal combinations. None of the items have been removed, but detailed images have been taken—although most of these are not yet available to the public.

The site's isolation has preserved its biological diversity as well, but the researchers are concerned that this may not last long. While they have kept the location secret to prevent looting, Honduras' forests are being rapidly destroyed to graze cattle, and there are fears the city will be revealed—and trashed—if a greedy rancher gets to the region.

The discovery of the ancient city is a consequence of efforts by documentary filmmakers Steve Elkins and Bill Benenson who identified the potential location and organized the aerial mapping that tipped Fisher off.