Archaeologists diving into a lake in the crater of a snowcapped volcano found wooden scepters shaped like lightning bolts that match 500-year-old descriptions by Spanish priests and conquerors writing about offerings to the Aztec rain god.

The lightning bolts — along with cones of copal incense and obsidian knives — were found during scuba-diving expeditions in one of the twin lakes of the extinct Nevado de Toluca volcano, at more than 13,800 feet above sea level.

Scientists must still conduct tests to determine the age of the findings, but the writings after the Spanish conquest in 1521 have led them to believe the offerings were left in the frigid lake west of Mexico City more than 500 years ago.