Sitting lonely and overgrown in Boston’s historic Franklin Park, these puddingstone ruins were once one of the only buildings ever designed by Frederick Law Olmsted, the father of landscape architecture, whose egalitarian ideals set the standard for public parks as a place equally accessible to anyone and protected from private interests.

Formed in the 19th century, Franklin Park is the largest and the crown jewel of the “Emerald Necklace”—a string of parks designed by Olmstead around greater Boston. However the historic park is often overlooked among Olmsted’s work, overshadowed by his crowning achievement, Central Park in Manhattan.

The building that now lies in ruins originally served as field house for Franklin Park’s athletic fields, housing changing rooms and a viewing area for sporting events below. Like many structures in Olmsted parks, it was designed to defer to the landscape that surrounded it. (Olmstead was an early leader of the conservation movement, advocating to preserve Niagara Falls and the Adirondacks in New York.) The building maintained a rustic feel, low to the ground and hidden by plantings. It was built from wood and puddingstone, a conglomerate rock abundant throughout the park and local to Boston.

Today, one can make out the original stone steps, an archway, water fountains, benches and other architectural features. The ruins remain a two-story structure. A path around the top of them still offers the original “Overlook” view down onto the Playstead sports area.

A fire in the 1940s wiped out most of the building. In 1966, Boston activist Elma Lewis revived the ruins as a concert venue with the popular Playhouse in the Park, hosting musical acts like the Billy Taylor Trio and Duke Ellington. Playhouse in the Park” continues in Franklin Park today, but the puddingstone ruins mostly go unused.