Archaeologists have discovered hundreds of metal spheres buried under an ancient pyramid near Mexico City. Scientists have no idea what the mysterious balls were for.
Jorge Zavala, an archaeologist at the National Institute of Anthropology and History in Mexico, described the discovery as "unprecedented."
The spheres have been hidden for the last 1800 years in one of the most important pre-Hispanic temples in Mexico City, writes gizmodo.com.
The city of Teotihuacan, just 45 kilometers from Mexico City, was once one of the largest cities in the world, with more than 100,000 inhabitants, at a time when only 200 million people lived on Earth. Its massive population makes it even more mysterious the total abandonment of the city in the year 700 of our era.
The people of Teotihuacan knew very well that they would never return to the city, so before fleeing from it, they filled their much-loved temples with waste and garbage. Their level was so high that it took scientists only a few years to plan how they could enter the temples.
Finally, a team of remote-controlled robots worked together to reveal what lay in the temples in Teotihuacan.
The robotic system, called the Tlaloque, includes a rover that transports two smaller mechanisms through temple tunnels. Once in a room, the trio of machines begin their work: one takes pictures of the space, while the other two move to film the entire space.
In this case, the infrared scanner came across rooms full of metal spheres that puzzled scientists.
They have a yellow color, being in fact made of oxidized pyrite, also called fake gold. With dimensions ranging between 4 and 12 centimeters in diameter, the spheres would have been, in the year 300 of our era, a shining gold.