A Mexican flag is seen at half mast at Zocalo Square during a march marking the 48th anniversary of the...
A Mexican flag is seen at half mast at Zocalo Square during a march marking the 48th anniversary of the 1968 Tlatelolco square massacre at which dozens, maybe hundreds, of protesters were gunned down by the army in a brutal repression of the student movement, in Mexico City, Mexico, October 2, 2016. REUTERS/Edgard Garrido