The $500 million, five-year Annenberg Challenge, started in 1993 by Walter H. Annenberg, generated an additional half-billion dollars to support its school reform project.

A recent study showed that more than $335 million in private funds and $215 million in public money came in from local, state and federal sources to support the 18 communities that make up the reform project nationwide.

The Annenberg Challenge Grant was launched at a White House ceremony in 1993 by former Ambassador Annenberg, who gave $500 million to establish his public-private partnership. The five-year challenge required a local match of funds in order to "energize, support and replicate" successful school reform programs throughout the country, The Annenberg Foundation states.

These 18 challenge sites have garnered more than 1,300 contributions in their communities, ranging from small donations to larger foundation gifts, which brought in $268.7 million nationally.

The William and Flora Hewlett Foundation donated $35 million in the San Francisco Bay Area. In Philadelphia, the William Penn Foundation and the Pew Charitable Trusts each contributed $10 million to the cause.

Other foundations donating more than $10 million were the John D. and Catherine T. MacArthur Foundation and the Joyce Foundation in Chicago, the Weingart Foundation in Los Angeles and the Brown Foundation in Houston

Annenberg's initial gift is being called the largest single private donation to American public education, and the Annenberg Institute for School Reform reports that since Walter Annenberg unveiled the challenge, 21 grants have been awarded.