Watch all new episodes of The Proof Is Out There, Tuesdays at 10/9c, and stay up to date on all of your favorite History Channel shows at https://history.com/schedule. A strange hum has disturbed people worldwide, but the source of this sound is unknown - experts investigate the cause of this amazing sonic mystery, in this clip from Season 1, "Mystery Hum and Mayans on Mars." #TheProofIsOutThere If you are interested in submitting videos or other content to be featured on Season 2 of The Proof Is Out There, head to https://www.history.com/shows/the-proof-is-out-there/articles/do-you-have-the-proof to agree to our Terms and Conditions and submit your content via our Submission Page. Subscribe for more from The Proof Is Out There and other great HISTORY shows: http://histv.co/SubscribeHistoryYT Watch more The Proof Is Out There on YouTube in this playlist: https://histv.co/WatchTheProofIsOutThere Check out exclusive HISTORY content: History Newsletter - https://histv.co/newsletter Website - https://histv.co/History Facebook - https://histv.co/Facebook Twitter - https://histv.co/Twitter The Proof Is Out There investigates the world’s most mysterious videos, photos, and audio recordings, and uses the best technology and experts to render a credible verdict. Each episode analyzes and passes verdicts on several seemingly impossible things “caught on film,” including giant beasts, UFOS, apocalyptic sounds, hairy humans, alleged mutants from the deep, conspiracies, and many other cases. Host and veteran journalist Tony Harris takes nothing for granted in a quest for answers, tracking down eyewitnesses, putting each photo or film through a battery of tests, calling out the hoaxes, and highlighting the most credible evidence in an attempt to better understand our world. HISTORY® is the leading destination for award-winning original series and specials that connect viewers with history in an informative, immersive, and entertaining manner across all platforms. The network’s all-original programming slate features a roster of hit series, premium documentaries, and scripted event programming.