Before there was Tiananmen Square, there was Tlatelolco Plaza. Just 10 days ahead of the 1968 Mexico City Games, army guns fired on a burgeoning movement of student protesters, setting off a government massacre—of anywhere from a handful to 3,000 students—that remains shrouded in mystery to this day. But 40 years later, reports NPR, official documents appear to shed some light on the bloodshed.
The Mexican Presidential Guard had apparently posted snipers to shoot at riot troops during the protest, making it seem as if the students had fired—to which the military responded predictably. Officials claimed only four students were killed, but eyewitnesses described hundreds of bodies being trucked away in military vehicles. Thousands were beaten and jailed, and many disappeared.