Rescuers make the signal for silence during the search for survivors in a flattened building in Mexico City on September 21, 2017, two days after a strong quake hit central Mexico killing at least 240 people. A powerful 7.1 earthquake shook Mexico City on Tuesday, causing panic among the megalopolis' 20 million inhabitants on the 32nd anniversary of a devastating 1985 quake. / AFP PHOTO / RONALDO SCHEMIDT