A gold bar found in a Mexico City park in 1981 was part of the Aztec treasure looted by Hernan Cortes and the Spanish conquistadors 500 years ago, a new study says.
The 1.93-kilogram bar was found by a construction worker during excavations for a new building along the Alameda, a picturesque park in the heart of the Mexican capital.
For 39 years, its origins remained a mystery.
But thanks to specialized X-rays, Mexico's National Institute of Anthropology and History (INAH) says it has now confirmed where the bar came from: the Spaniards' hasty, though temporary, retreat during the so-called "Noche Triste," or "Sad Night."
That night -- June 30, 1520 -- the Aztecs, furious over the slaughter of their nobles and priests, drove the Spanish invaders from their capital, Tenochtitlan.
The conquistadors escaped with as much looted Aztec treasure as they could carry, including, apparently, the gold bar in question.