In every corner of the world, archaeologists have found strange, elongated skulls. Did our ancestors modify the shape of their skulls to resemble extraterrestrials? And might it even be possible that some of these skulls are of otherworldly origin?

High above the Giza Plateau stands Egypt's most mysterious ancient site: the Lost Pyramid of Abu Rawash; today, it lies in ruins, but some researchers believe these stone blocks hold profound secrets about an extraterrestrial civilization that existed in ancient Egypt long before our recorded history.

In the western Pacific Ocean is a vast area known as Oceania that is home to the world's most remote and mysterious islands. They are known for massive stone structures, statuary strange figures, and countless legends of otherworldly visitors. Could it be that these islands are the remnants of a lost alien civilization?

Host Giorgio Tsoukalos probes the series archives to explore remarkable ancient structures that defy conventional explanation. From the precisely cut stone blocks at Puma Punku, to the gigantic temples of Malta, and the megalithic city of Nan Madol, could these mysterious sites contain evidence of extraterrestrial contact in the distant past?

From a stone circle in Turkey that challenges the timeline of human history to gigantic stone spheres in Bosnia and Egypt’s most unusual tombs, could these monuments provide proof of extraterrestrial visitation?