Built in 1924 by the Metropolitan Water District, Lake Hollywood is the most secluded body of water in the area. The dam that restricts it was designed by William Mulholland, who also designed the aqueducts that provide LA with most of its drinking water. Although the lake is not accessible to the general public, many people come here to walk and jog along its perimeter path, which also affords great views of the Hollywood sign and some of LA's architectural jewels. Check accessibility via the website before making a trip out.