After almost a decade of painstaking work, researchers have unearthed an amazing 50,000 relics from a tunnel in the ancient city of Teotihuacan—and they believe the biggest prizes still await. The tunnel below the site around 30 miles away from Mexico City was discovered in 2003 after having been sealed for around 1,800 years, and remote-controlled robots explored it before human archaeologists got to work, reports Reuters. Among the artifacts uncovered: obsidian blades, seeds, shells, carved stone, and jewelry. A large offering found below the "Temple of the Plumed Serpent" has led researchers to believe that three chambers, which have yet to be excavated and sit just beyond the items, could be the tombs of the city's mysterious rulers.
"Because this is one of the most sacred places in all Teotihuacan, we believe that it could have been used for the rulers to ... acquire divine endowment allowing them to rule on the surface," the project leader tells the AP. No written records of the inhabitants of the once-dominant city—whose name means "abode of the gods " in the Aztec language—exist, and no remains of its rulers have ever been found, leaving its leadership structure unknown. Remains could indicate, for example, if rule was hereditary, notes the BBC. To date, the team has excavated about 2 feet into the chambers; getting all the way through is expected to take a minimum of a year. (Earlier in the excavation, archaeologists found hundreds of strange metal orbs.)