The summary is:
The video is about three mysteries that suggest the presence of ancient aliens: the Dogon tribe's knowledge of Sirius B, the Tiwanaku city's stone structures and elongated skulls, and the Pyramids of Giza's alignment and precision. The video presents some facts and theories about these mysteries, but also some skepticism and humor from one of the hosts. The video ends by saying that the existence of extraterrestrials is unsolved.
Here are the key facts extracted from the text:
1. The text is a transcript of a video from BuzzFeed Unsolved, a series that discusses mysteries and paranormal phenomena.
2. The video covers three mysteries that suggest the presence of ancient aliens: the Dogon and Sirius B, the city of Tiwanaku, and the Pyramids of Giza.
3. The Dogon are a tribal group in west Africa that have knowledge of astronomy that some believe was taught by amphibious beings from the Sirius star system.
4. Tiwanaku is an ancient city in Bolivia that used massive stones and precise carvings that some believe were aided by alien technology or visitors.
5. The Pyramids of Giza are structures in Egypt that align with magnetic north and Orion's belt, and have mathematical and engineering features that some believe were beyond the capabilities of the ancient Egyptians.