A year ago I volunteered at the Little Light Uganda. The NGO operates a school for children who living in one of the poorest slums in Africa. Little Light supports about 300 families and promotes several projects such as health, education, sponsored funding, community contribution, a women's empowerment group and a youth group.
The experience of volunteering in Uganda was extraordinary because the volunteers get to promote projects that have a huge impact on the lives of people who really needs it. If you seeking a pure place where you can express your true values than this is the right place for you.