Construction Worker Stumbles on a Gigantic Gold Bar Under a Street, Was Left Behind by a Fleeing Spanish Invader

In 2020, researchers uncovered that a gold bar they discovered in 1981 under a Mexico City street had connections with the Noche Triste, or "Night of Sadness." Noche Triste was a historical event when Spanish invaders retreated from the Aztec capital of Tenochtitlán on June 30, 1520, according to Smithsonian Magazine. After analyzing the gold's composition researchers concluded that the gold bar was one of the objects conquistador Hernán Cortés' soldiers escaped with while being attacked by Aztec civilians. 

The gold bar was spotted by construction workers 16 feet below ground. It weighed around 4.4-pound and experts analyzed it through an X-ray fluorescence analysis to determine its origins. The chemical composition of the bar was similar to the gold objects found near Templo Mayor, the central temple of Tenochtitlán. This collection was cast sometime between 1519 and 1520. The bar is 26.2cm (10.3in) long, 5.4cm wide, and 1.4cm thick, stated The Guardian.  

According to historians, Cortés ordered the Aztec treasury to be melted into gold between 1519 and 1520. The location of the discovery along with the timing when it was cast made researchers speculate about its connection with Noche Triste. Cortés gave the order to change the treasures into gold bars so that it would be easier for him and his comrades to transport them to Europe. During Noche Triste, the whole city erupted into rebellion, and Cortés and his fellow soldiers ran for their lives. The group was heavily weighed down by the gold they were trying to smuggle out of the city borders. Researchers claim that many soldiers drowned with their loot in a now dried-up canal that fed into Lake Texcoco, according to Live Science. The gold bar was in this loot, which after four centuries appeared in front of the workers. 

Leonardo López Luján, the director of the Templo Mayor Project was elated by the discovery. He called the bar  "a dramatic material witness of the Spanish conquest and unique archaeological testimony of the so-called 'Sad Night.'"  Mexico's National Institute of Anthropology and History (INAH) and the National Autonomous University of Mexico (UNAM) were the organizations involved in the examination of the gold bar.

They found that the bar was composed of 76% gold, 21% silver and 3% copper. Workers came face to face with the bar while digging for a central bank in Mexico City. The bar was placed in the speculated route undertaken by conquistador Hernán Cortés while escaping Aztec people. Despite all the evidence, researchers have not conclusively determined the bar as part of plundered Aztec treasure. Currently, it is on display at the National Museum of Anthropology in Mexico City.

For researchers the discovery was very valuable, as before this finding experts only had historical documents to know about the end of the Aztec empire, The Guardian stated. Such findings will help them to expand their knowledge about the period. "The gold bar is a unique historical testimony to a transcendent moment in world history," said López Luján.