Sun Tunnels: Shifting Shadows  depicts the shifting patterns of light and shadow over the course of a long July summer day inside one tunnel of Nancy Holt’s landmark earthwork Sun Tunnels (1973-76), located in Utah’s Great Basin Desert. The sculpture comprises four concrete structures arranged in an X-formation, positioned to frame the sun as it rises and sets at the solstices.

Commissioned through the U.S. General Services Administration’s (GSA) Art-in-Architecture program, Annual Ring is a site-responsive sculpture that uses solar alignment to register cyclical changes in time and light. Constructed from steel and organized around a hemispherical form, the work combines a raised ring with a dome punctuated by apertures that frame the sky and direct sunlight into the sculpture’s interior. As with all of Holt’s public sculptures, the work was fabricated locally.