A pathway of liquid mercury has been found under the Pyramid of the Feathered Serpent, the third largest pyramid of Teotihuacan ruins in central Mexico. Archaeologists are hopeful that this could be an indicator that leads them to find the tomb of a King or Queen of the mysterious Teotihuacan people.
http://www.theguardian.com/world/2015/apr/24/liquid-mercury-mexican-pyramid-teotihuacan