Ancient Aliens

Giorgio Tsoukalos takes a look back at some of the structures visited all over the world that could provide undeniable evidence of extraterrestrial contact.

Considered by many to be the greatest civilization in the history of the Americas, the Maya thrived for more than 2,000 years; today new evidence is being discovered that completely upends our understanding of this ancient culture, and might provide evidence that the Maya came in contact with extraterrestrial visitors.

Counting down 10 discoveries that challenge traditional beliefs about human history, from a lost city hidden in the Andes to mysterious metal spheres that are not of this world and a sunken city that is said to be the home of the gods.

Counting down ten mysterious monoliths; from a 500-ton stone believed to represent an ancient UFO, to giant statues said to have been created with advanced technology, and ornate pillars that depict otherworldly visitors.

"Ancient Aliens" is counting down ten compelling UFO crashes that have been reported across the globe; from an acorn-shaped object that crashed in the woods of rural Pennsylvania, to a mysterious craft that washed ashore in Japan.

Counting down ten unexplainable technologies in history, from mysterious golden orbs discovered in Mexico and a sacred wooden box that could communicate with the heavens to an ancient tomb that is said to depict an astronaut.