Environmental Art is loosely related to the present-day installation art, but distinguished by its relationship to staged events and relationship to the viewer. Generally speaking, in Environmental Art, an artist devises an entire closed space where the viewer can withdraw entirely from the rest of a gallery, museum, etc. The artist’s creation then absorbs and envelops the viewer. Chronologically artists began creating environments as early as the 1950s, and in the 1960s the form became popular. Contemporaneous with the genesis of environmental art were Happenings. The artist Red Groom began staging his own version of a Happening, which evolved into designing entire rooms with color and cut-out people, where he could stage his events. The emphasis on controlling the entire atmosphere is essential in environmental art, and artists use lights, scents, colors, figures and sound to develop the space. Other leaders in environmental art are George Segal, Niki de Saint Phalle and Edward Kienholz. Often environmental art is said, in the loosest use of the term, to describe work completed in the natural environment, or work that involves aspects of the natural environment, such as Christo and Jeanne-Claude’s work does.