One of my favorite conspiracy theories revolves around the Denver Airport, which ties into CIA mind control, extraterrestrials, devil worship, sex slavery, the Masons, the Mayan calendar and the Queen of England. The article linked above explores this through the lens of Coast to Coast radio, an overnight radio show devoted to the paranormal that was once broadcast from the Kingdom of Nye with Art Bell at the helm, but now administered by his disciple George Noory. But to truly appreciate the mystery of DIA, you must contemplate its truly bizarre murals.
What fascinates me about this conspiracy is how hard it labors to explain things -- the delays in construction, the inconvenient location, the Byzantine baggage system, the amateurish mural painting that are probably just the result of an incompetent bureaucracy, poor planning, and feather-bedding contractors. If only there were schemes this far-reaching and nefarious. But then maybe by disbelieving, I'm living in a dream world. Maybe skepticism is just our last line of psychological defense.