A cenote at Chichen Itza swallowed offerings for centuries, and an American consul dredged a fair number of them back out.
What came out of the water
The Cenote Sagrado, a large natural sinkhole connected by causeway to the site's centre, was dredged between 1904 and 1910 by Edward Herbert Thompson, an American who had bought the surrounding hacienda partly to investigate it. He recovered gold and jade objects, incense, textiles, and human remains, evidence generally read as offerings and occasional sacrifice made by casting objects and people into the water, likely tied to rain and fertility appeals to the Maya god Chaac. Much of what he recovered left Mexico for Harvard's Peabody Museum, a removal Mexico later disputed; some pieces were eventually returned.
Toltec, or just similar
Architecture and imagery at Chichen Itza, including feathered serpent columns and reclining Chac Mool figures, closely resemble styles from Tula in central Mexico, once home to the Toltecs. Earlier scholarship read this as evidence of a Toltec conquest of the Maya city; more recent work argues instead for a shared cultural and trade network across Mesoamerica without requiring an actual military takeover, and the question remains actively debated rather than settled.