It was a mystery in the desert for 50 Years. Now, in a remote Nevada valley, the artist Michael Heizer’s astonishing megasculpture, “City,” is finally revealed. A mile and a half long and nearly half a mile wide, “City,” sits smack in the middle of a remote stretch of the high desert, where what passes for a neighbor is Area 51. The nearest blacktop is an hour’s drive away, on a dusty, bumpy, former livestock trail, across a couple of mountain ranges.

Exquisitely groomed dirt mounds, roads, buttes and depressions similar to dry lake beds spread out in different directions and no immediately obvious order. At both ends of the site, monumental structures evoke ancient ruins. Now, half a century and $40 million after Heizer stuck his first shovel in the ground, “City” is finally open to visitors.