New discoveries at Mexico's famed Teotihuacan ruins

This Aug. 6, 2014 photo released by Mexico's National Institute of Anthropology and History (INAH) shows a sculpture unearthed at the Teotihuacan archeological site in Mexico. Mexican archaeologists have concluded a yearslong exploration of a tunnel sealed nearly 2,000 years ago at the ancient city of Teotihuacan and found thousands of relics. Teotihuacan dominated central Mexico centuries before the rise of the Aztecs in the 14th century. (AP Photo/Proyecto Tlalocan, INAH)

This Nov. 19, 2013 photo released by Mexico's National Institute of Anthropology and History (INAH), shows sculptures unearthed by investigators at the Teotihuacan archeological site in Mexico. Mexican archaeologists have concluded a yearslong exploration of a tunnel sealed nearly 2,000 years ago at the ancient city of Teotihuacan and found thousands of relics. Teotihuacan dominated central Mexico centuries before the rise of the Aztecs in the 14th century. (AP Photo/Proyecto Tlalocan, INAH)

This May 22, 2014 photo released by Mexico's National Institute of Anthropology and History (INAH) shows sculptures unearthed at the Teotihuacan archeological site in Mexico. Mexican archaeologists have concluded a yearslong exploration of a tunnel sealed nearly 2,000 years ago at the ancient city of Teotihuacan and found thousands of relics. Teotihuacan dominated central Mexico centuries before the rise of the Aztecs in the 14th century. (AP Photo/Proyecto Tlalocan, INAH)

This Oct. 2, 2014 photo released by Mexico's National Institute of Anthropology and History (INAH) shows shells unearthed by investigators at the Teotihuacan archeological site in Mexico. Mexican archaeologists have concluded a yearslong exploration of a tunnel sealed nearly 2,000 years ago at the ancient city of Teotihuacan and found thousands of relics. Teotihuacan dominated central Mexico centuries before the rise of the Aztecs in the 14th century. (AP Photo/Proyecto Tlalocan, INAH)

This May 22, 2014 photo released by Mexico's National Institute of Anthropology and History (INAH), shows sculptures and shells unearthed by investigators at the Teotihuacan archeological site in Mexico. Mexican archaeologists have concluded a yearslong exploration of a tunnel sealed nearly 2,000 years ago at the ancient city of Teotihuacan and found thousands of relics. Teotihuacan dominated central Mexico centuries before the rise of the Aztecs in the 14th century. (AP Photo/Proyecto Tlalocan, INAH)