Colombia on Wednesday declared three days of mourning for victims of an earthquake that demolished buildings in the west of the country, killing more than 200 people. At 7.4 magnitude, Monday's quake was the strongest to hit Colombia in a century. The first two days after an earthquake are crucial for finding survivors under rubble, with some experts saying there is a 72-hour window, after which hopes quickly tail off. Perez said a local resident heard cries for help beneath the rubble and joined neighbors in removing debris before professional rescuers arrived. The quake overwhelmed parts of the health system, turning the rescue effort into one of Colombia's largest disaster responses in years.