Michael Heizer was just 27 years old when he began work on "City" in 1970. Now, 50 years later, the reclusive American artist is finally ready to showcase his life's work. The 1.5-mile-long complex, which cost $40 million to build, opened to the public on September 2, 2022. It is the largest contemporary artwork ever built. The exact location of "City" is a secret. But it lies in a remote valley in Nevada's Great Basin Desert.