EHDD's architectural design for the Exploratorium's new 330,000-square-foot indoor-outdoor facility in San Francisco aims for net-zero energy. The design called for renovation of a 1915 building on Pier 15. The concrete cladding was preserved and the concrete exterior was slightly modified. "Our strategy was not to paint it over and make it look new," said EHDD principal Marc L'Italien. "But to show the passage of time to the degree we could."