One of the true pioneers of minimalist installation art, Walter De Maria died Thursday at the age 77 of an apparent stroke in New York City. He was born in California and studied history and art at UC Berkeley training as a painter but De Maria soon turned to sculpture and began using other media. The Lightning Field (1977), middle, is De Maria’s best-known work which consists of 400 stainless steel posts arranged in a calculated grid over an area of 1 mile. In 1979, De Maria meticulously arranged five hundred brass rods for The Broken Kilometer, top, a permanent installation at 393 West Broadway in New York City. The New York Earth Room (1977), bottom, is a 3,600-square-foot room filled to a depth of 22 inches with 250 cubic yards of earth which was then permanently installed in 1980 at 141 Wooster Street, also in New York. Similar to The Lightning Field, The Broken Kilometer and New York Earth Room installations remain on continuous view, maintained by Dia Art Foundation.