The crown jewel of Bel Air, a 4-acre lot with 360-degree views, will soon be home to the largest residence built in the United States this century. Located at the very top of the prestigious Los Angeles neighborhood, the lot sports completely unobstructed views. The Pacific Ocean, neighboring Beverly Hills, downtown Los Angeles, and the San Fernando Valley will all be visible from various rooms in the soon-to-be-completed modern home. The 20-month construction project will yield a 74,000-square-foot main resid…