Helmut Scholle pushes open the narrow wooden door flanked by small windows and ducks his head as he steps into the cave. Behind the simple rocky exterior is a home, complete with distinct rooms, a chimney, and cozy furniture. Two things become obvious. Despite the frigid winter air, it’s relatively pleasant inside. And the marks on the rugged walls—signs of repeated chipping and chiseling—indicate that this home required a monumental human effort to make. The cave, Scholle reveals, was carved into the rock by migrant farmworkers in desperate need of…