May 28, 1987, was Border Guard Day in the Soviet Union, a commemoration of the military's service in preserving the country's frontiers during the Cold War. So it was particularly galling for Soviet authorities that Mathias Rust, a 19-year-old amateur pilot from East Germany, chose the occasion to expose the vulnerability of one of the country's iconic locations. At about 7:30 p.m., Rust landed a blue-and-white Cessna Skyhawk 172, a small single-engine plane, in Moscow's Red Square as onlookers gawked in astonishment. Rust had time to coolly sign a few autographs for the crowd before flabbergasted authorities apprehended him. It was one of aviation's stranger feats at the time, few aircraft were permitted to enter Russian airspace, let alone Moscow's, and yet Rust had flown unimpeded all the way from Helsinki. Exposing chinks in the Soviet armor carried consequences, however. Rust was sentenced to four years in a labor camp for violating flight rules and "malicious hooliganism."