Casino Teepee of Light
Prior Lake, Minnesota
The Shakopee Mdewakanton Sioux Community opened the Mystic Lake Casino in 1992, Minnesota's first (and largest) gambling hall. Encouraging gamblers to "follow the lights," the casino installed a dozen high-powered searchlights, angled upward and inward to form a ghostlike teepee. The lights were originally so bright that the FAA forced the Sioux to lower the wattage, fearful that they might blind airplane pilots and passengers that passed through them.
From miles away the light-pole beams become invisible, but when there's a thin deck of clouds at night they form a circle of dots in the sky, which has led to a number of reports of UFOs.