The Dia Art Foundation is well known for its stewardship of two of the greatest pieces of American land art: Robert Smithson’s “Spiral Jetty” in Utah and Walter De Maria’s “Lightning Field” in New Mexico.

In 2015, after years of planning, it will open an ambitious new long-term project that is intended to ask provocative questions about what “American” means and to push the boundaries of the foundation’s roots in the Minimalist and Conceptual movements of the 1960s and ’70s.