For decades, the iconic art collection assembled by Dr. Albert Barnes was displayed at his summer estate turned museum and arboretum in Merion, Pennsylvania. Now relocated along Philadelphia’s Museum Mile, the priceless collection is accessible to the public as never before. Conceived as a gallery within a garden and a garden within a gallery, the design honors the original Barnes estate designed by Paul Philippe Cret and provides visitors with a highly personal and contemplative experience. OLIN’s design captures the spirit of the original site, fits into the urban context, and implements contemporary sustainable practices. The gallery building opens to two separate outdoor spaces—one a lush garden and terrace adjacent to the museum’s café, replete with plantings characteristic of the historic gardens in Merion; the other is a paved open terrace overlooking the parkway, suitable for more intimate events, decorated with antique benches, platforms for seating, loose furniture, a fireplace and a collection of flowering trees. Within the gallery, a central courtyard has been left open to the sky. Graceful allées of trees surround the site and line the entranceways along with linear pools. Vine-covered walls and hedges discretely mask the visitor parking and bus loading points. An underground cistern captures stormwater for on-site irrigation, conserving resources and contributing to the project’s LEED Platinum certification.