A magnitude-7.8 earthquake devastated Nepal and the entire Katmandu Valley region, leveling buildings and killing more than 1,400, with the death toll continuing to rise.
Such a powerful quake would result in destruction anywhere, but in a nation as poverty-stricken as Nepal, its citizens are particularly vulnerable.
Aid groups worldwide have mobilized to help.
The British Red Cross was on the ground, helping to rescue and recover those trapped in the rubble.
"Our people on the ground have found the overall situation to have been worse than their worst fears," said Devendra Tak, who works for Save the Children in India.
"This is indeed one of the largest and possibly most complex earthquake situations in recent times," Tak said, referring to the densely populated area. "It will be a challenge to maneuver a relief operation amidst this large-scale destruction."
The humanitarian aid group Oxfam said it was sending a team of technical experts from Britain to provide clean water, sanitation and emergency food supplies.
"Communication is currently very difficult," said Cecilia Keizer, Oxfam country director in Nepal."Telephone lines are down and the electricity has been cut off, making charging mobile phones difficult. The water is also cut off."
The organization CARE said it is coordinating with other agencies to assist up to 75,000 people.
"I think 100 percent of people in Katmandu are not inside their homes," said Santosh Sharma, an emergency response coordinator with CARE in Nepal. "Everyone is outside with no tents or blankets. This are very difficult conditions for women, children and elderly people. It's very cold for them, and the aftershocks just keep coming for hours. Everyone is afraid to go indoors, so we will all sleep outside in the cold tonight."
MercyCorps, Direct Relief and Habitat for Humanity are also directing funds toward the Nepal earthquake response.
People can also donate $10 to UNICEF by texting "Nepal" to 864233.
Before contributing to an aid group, research its legitimacy. Sites such asCharityNavigator.org, which evaluates charities' accountability and finances, can help you avoid scams that prey on people's generosity in the wake of major disasters.