ATLANTA --- The Aga Khan, the billionaire philanthropist and spiritual leader of 20 million Muslims worldwide, ended an eight-day tour of the U.S. on Friday in Atlanta by stressing the importance of understanding, tolerance and global citizenship in education -- especially in developing countries.

His trip, which also included stops in Texas, Illinois and California, was part of the Shia Ismaili Muslim commemoration of the Golden Jubilee, which marks the Aga Khan's 50th year as imam of the religious sect.

In his speech at North Atlanta High School, he tried to raise awareness about the Aga Khan Academies, a $1 billion education initiative that will build 18 schools in 14 countries in Africa, Central and South Asia and the Middle East.

The project grew out of a need to develop well-educated, global citizens who would make a difference in their communities, the Aga Khan told the audience.

"Our Academies program is rooted in the conviction that effective, indigenous leadership will be the key to progress in the developing world, and as the pace of change accelerates, it is clear that the human mind and heart will be the central factors in determining social wealth," he said.

The Aga Khan, who was born and educated in Switzerland, is a Harvard-educated businessman who is a descendant of the Prophet Muhammad. In his capacity as imam, he is also the chairman of the Aga Khan Development Network, a group of private, nondenominational development agencies focused on social, cultural and economic development.

The Aga Khan Academies are an initiative of the network's Aga Khan Education Services, and under the plan, 18 schools are planned in 14 countries at a cost of about $50 million per school -- a commitment of nearly $1 billion. The first school opened in Mombasa, Kenya, in 2003, and others are planned in India, Bangladesh, Mozambique, Madagascar, Afghanistan, Pakistan, Syria, Tanzania and Uganda.

The academy curriculum is based on the International Baccalaureate program, which is derived from a program rooted in academics, critical thinking and a respect and appreciation for cultural diversity.