The City of Sarasota will participate in the international energy conservation effort known as Earth Hour by darkening City Hall, 1565 First Street, and the old Federal Building, 111 S. Orange Ave., Sat., March 27, 2010 from 8:30 pm to 9:30 pm. Decorative lights on the Ringling Bridge and Season of Sculpture along the bayfront also will be extinguished during Earth Hour. Residents are encouraged to participate as well.