Josh explores the deep jungles and ruins of the Yucatan Peninsula in Mexico where he investigates the fall of the Mayan Empire. New evidence suggests that cenotes, dark flooded underground caverns, under Mayan cities may hold the key to understanding the collapse of the once great Mayan people. Josh's journey begins in Cancun. He drives down the coast to the ruins of Tulum, the City of the Dawn. There, Josh meets with archaeologist Carmen Rojas who tells about the size and reach of the Mayan Empire. Next, Josh heads to the ruins of Coba, where he climbs up the tallest Mayan ruin: the Ancient Pyramid. From atop the pyramid, Josh takes in the wide view of the surrounding jungle and marvels at the immense structures the Mayans created. After leaving Coba, Josh heads back to Tulum where he takes part in the annual Day of the Dead festival. He gets in the spirit by sampling the local delicacies, dancing in the street, and even getting a Day of the Dead makeover.