Volunteers help remove debris of a building that collapsed at Durbar Square, after an earthquake in Kathmandu, Nepal, Saturday, April 25, 2015. A strong magnitude-7.9 earthquake shook Nepal's capital and the densely populated Kathmandu Valley before noon Saturday, causing extensive damage with toppled walls and collapsed buildings, officials said. (AP Photo/ Niranjan Shrestha)

Photos: Earthquake strikes Nepal

An earthquake with a 7.8 preliminary magnitude struck Nepal on Saturday, April 25, 2015, resulting in mass casualties.