Artist Leo Tanguma painted two large murals for DIA that have fueled decades of speculation. 'Children of the World Dream of Peace' depicts a soldier in a gas mask terrorizing people with a scimitar, dead children, and burning buildings - followed by scenes of children beating the sword into plowshares. 'In Peace and Harmony with Nature' shows environmental devastation giving way to ecological restoration. Tanguma says they depict the triumph of peace over war and humanity's reconciliation with nature. Conspiracists see them as blueprints for genocide, mind control, and the New World Order's plan to reduce global population. The murals' undeniably disturbing imagery lends itself to interpretation.

Outside the terminal stands 'Blue Mustang,' a 32-foot fiberglass sculpture with glowing red eyes that locals call 'Blucifer.' Artist Luis Jiménez created it to represent the wild spirit of the American West. He didn't live to see it installed - in 2006, a section of the sculpture fell on him and severed an artery, killing him. His family completed the work, which was installed in 2008. The demonic appearance and fatal origin story made it infamous. Petitions to remove it gather signatures regularly. The eyes really do glow red at night, illuminated from within. For conspiracy theorists, Blucifer is a death horse, harbinger of apocalypse. For Denver, it's the city's most divisive public art.

DIA has an unusually extensive underground infrastructure. The automated baggage system - which never worked properly and was eventually abandoned - required massive tunnels. There are also underground tram tunnels connecting the concourses. Conspiracy theorists see these tunnels as suspicious: why so many? Why so large? The leading theory holds that the visible airport is just a cover for vast underground facilities - bunkers for government elites, prison camps for dissidents, or bases for aliens or reptilian beings. The tunnels do exist and are extensive; their purpose is officially mundane but their scale fuels speculation.

A dedication capstone in the Great Hall credits the 'New World Airport Commission' - a now-defunct civic group whose name unfortunately echoes 'New World Order.' Masonic symbols appear on the capstone, because Freemasons participated in the dedication ceremony - a common practice for public buildings. The runway layout, from certain angles on certain maps, resembles a swastika - or simply runways arranged for prevailing winds. Strange phrases and symbols appear in the floor's decorative stonework. Everything can be interpreted as sinister if you're looking for sinister. DIA has learned to embrace it, installing 'construction' barriers that joke about adding 'secret meeting rooms.'

Denver International Airport is located 25 miles northeast of downtown Denver. The 'weird' attractions are throughout the facility: Leo Tanguma's murals are in the Jeppesen Terminal (level 5); Blue Mustang stands outside between Peña Boulevard and the terminal; the Masonic capstone is in the Great Hall; gargoyle sculptures 'emerging from suitcases' are in the baggage claim. The underground train between concourses passes through the tunnels but reveals nothing sinister. DIA's official public art tours are offered periodically. The 'New World Order' gift shop items are sold at various airport stores. For conspiracy enthusiasts, simply being in the building is the point - you're inside the supposed headquarters.