The WPA's initial appropriation in 1935 was for $4.9 billion (about 6.7 percent of the 1935 GDP). Headed by Harry Hopkins, the WPA provided paid jobs to the unemployed during the Great Depression in the United States, while building up the nation's public infrastructure, such as parks, schools and roads. Most of the jobs were in construction, building more than of streets and over 10,000 bridges, in addition to many airports and much housing. The largest single project of the WPA was the Tennessee Valley Authority.