Conspiracy theorists claim a secret bunker has been buried beneath Denver International Airport as the US government prepare for the apocalyspe. And, they say there's plenty of evidence to back up their incredible claim.
One video examines several theories, from murals and artwork to secret blueprints, as they seek to prove something suspicious is occurring under the Colorado site.
The clip, uploaded by UFO hunter Tyler Glockner from Secure Team 10, starts by claiming: "Something is very wrong with the Denver International Airport."
Tyler added: "There have been a range of conspiracy theories about Denver airport.
"The most known is that the airport is actually a massive base, said to be underground.
"It's almost as if they [the government] built this airport with some sort of information that we don't know about that something bad is going to happen in the new future."
The airport first opened on February 28, 1995.
Visitors reported seeing a variety of a strange symbols and images, which depicted apocalyptic scenes that appeared to be linked to the Freemasons.
Some murals also appear to contain themes that refer to future military oppression and a one-world government.
Tyler then draws attention to the 'demonic' blue horse statue which stands at the front of the airport.
The sculpture was created by artist Luis Jimenez. But before the work was finished, Jimenez died when part of the horse fell on him and severed one of his arteries.
A plaque at the front of the airport has also caused a buzz among conspiracy theorists, not least because of the masonic symbol inscribed on it.
Underneath the stone, a time capsule has been buried, which is to be opened by 'the people of Colorado' in 2094.
But Tyler questions what is so specific about this year: "Do they know something we don't?"
A third mystery is that the stone references the New World Airport Commission, an organisation that Tyler claims does not exist.
He adds: "It's all very cryptic."
But it's Tyler's final claim that is the biggest.
He suggests that there are five huge government bases buried underneath the airport, exclusively for government officials to hide in should the apocalypse ever occur.
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Tyler adds: "According to an airport spokesman, these building are now being used as 'storage'."
"It's no secret that there is an underground structure beneath the airport because they've actually created tramways down there, tunnels for trains."