Christo and Jeanne-Claude, Running Fence, 1972-76
Christo and Jeanne-Claude created earthworks that were different than the permanent pieces by artists like Smithson and Heizer. Instead, these site-specific installations stayed up only for a few weeks at a time. However, the most important parts of the project was the planning and execution.
One of my most favorite earthworks. I recall sitting in art history lecture, talking about how many people this work brought together, and tears in my eyes about the beauty of it.