One of the leaders in the 1960's and 70's in the movement to  free art from the confines of the gallery system, he was pre-  
One of the leaders in the 1960's and 70's in the movement to  free art from the confines of the gallery system, he was pre-  occupied with what he termed 'the dialectic between the site and  non-site.' FTP, name this Earth-Works artist, best known for his  monumental works such as Amarillo ramp, the project he died  working on, and Spiral Jetty.
One of the leaders in the 1960's and 70's in the movement to  free art from the confines of the gallery system, he was pre-  
Robert {Smithson}