If you’ve noticed something beautiful while driving through Los Angeles lately, you’re onto something artsy. The city is currently in the midst of Current:LA Water, a public art biennial with the goal of bringing the city’s most critical issues into a conversation using the power of contemporary art. And one of the project’s most ambitious works of art is one that draws on one of the city’s most fraught symbols, reports FastCoExist’s Adele Peters: The snaking, nearly dead Los Angeles River.

“UnderLA” is a collaboration between media artists Refik Anadol and Peggy Weil. Located at the mouth of the river and at the iconic First Street Bridge in eastern downtown, the installation takes over a stretch of the river’s concrete banks with projections of lithologic soil samples taken by USGS geologists from the surface to 1,400 feet underground. Each sample reflects older and older pieces of rock going back as far as 2.5 million years. The samples were taken inside two monitoring wells in Los Angeles—a reminder, the duo says on the project’s website, “that LA’s aquifers are stressed by the continuing drought.”