William (Bill) H. Gates III,

co-chair and trustee (right), meets with officials in the Batallón de San Patricio Public Library in Mexico City.

Melinda French Gates,

co-chair and trustee (right), listens to a doctor at a health clinic near Hanoi, Vietnam.

Warren Buffett,

trustee (right), speaks to the media in New York City after announcing his historic gift to philanthropy.

William H. Gates Sr.,

co-chair (center), celebrates the fifth anniversary of the Washington State Achievers Program.

Patty Stonesifer,

chief executive officer, visits with children at the Holy Cross Day Care and Hospice in Gaborone, Botswana.

Sylvia Mathews Burwell,

president, Global Development Program (second from right), listens to a microfinance group in Nigeria.

Tadataka Yamada, M.D.,

president, Global Health Program (center), talks to doctors at a health conference in Washington, D.C.

Allan C. Golston,

president, U.S. Program, visits the Jefferson Parish East Bank Regional Library in Louisiana.

Cheryl Scott,

chief operating officer, breaks ground on a parking garage near the foundation’s future headquarters in Seattle, Washington.