On July 11, 1991 a total solar eclipse began over the Pacific Ocean and Hawaii, moved over Mexico and Central America and down to South America, ending in Brazil. In Mexico City, people reported seeing much more than a rare celestial event. In what has been called one of the largest mass UFO sightings ever, a number of Mexicans reported seeing a strange hovering craft as they were watching the eclipse. Sightings also apparently happened in other Mexican cities, but it's hard not to wonder whether some of these people were just seeing spots because they weren't wearing their eclipse safety glasses.