Lost Worlds: Aliens from Earth‪?‬ Unexplainable

Was there a technologically advanced species living on Earth long before humans? And if one had existed, how would we know?
This is the first episode of our new four-part series, Lost Worlds.
For more, go to http://vox.com/unexplainable
It’s a great place to view show transcripts and read more about the topics on our show.
Also, email us! unexplainable@vox.com
We read every email.
Support Unexplainable by making a financial contribution to Vox! bit.ly/givepodcasts
Learn more about your ad choices. Visit podcastchoices.com/adchoices
Learn more about your ad choices. Visit podcastchoices.com/adchoices