Mount Umunhum (Ohlone, meaning resting place of the hummingbird) is the fourth-highest peak in the Santa Cruz Mountains of California (after Loma Prieta, Crystal Peak, and Mt. Chual). The mountain is situated in Santa Clara County, southeast of Los Gatos and south of South San Jose. The peak is sometimes referred to as "Mount Um" by locals. It is a well-known landmark in the Bay Area which can be recognized in Santa Clara Valley by the five-story concrete, radar tower building, known locally as "The Cube" or "The Box", that sits atop the summit. The tower construction began in 1960 and completed in 1962. It supported an 85.5-ton General Electric model AN/FPS-24 long range search radar antenna "sail" used to detect incoming hostile aircraft during the Cold War.