Presidio Tunnel Tops is a 14-acre national park landscape built atop highway tunnels in the Presidio, reconnecting San Francisco’s historic post with its waterfront. Opened in July 2022, the park was designed by James Corner Field Operations as an inclusive gathering place with panoramic views. Organic-Lock Stabilized Aggregate (OLSA) forms the park’s network of wide, curving trails, blending into native coastal gardens while providing firm, accessible footing. The permeable, natural-looking pathways help manage runoff on the sculpted slopes and withstand heavy foot traffic in this highly visited urban national park.