William Donald Schaefer stood at the edge of the National Aquarium’s 70,000-gallon seal pool and looked out at the reporters and spectators surrounding the tank. It was July 1981, and the Aquarium was a month behind schedule. The project was a $21.5-million risk, but it was a risk Schaefer knew he needed to take to help revive his city, struggling beneath the weight of empty row houses, unemployment, and high crime. As part of his Inner Harbor project, he believed the Aquarium would help restore Baltimore’s image and faltering economy, and he was willing to swim with the seals to prove it.

Wearing a striped Victorian-era swimsuit and straw hat, Schaefer took a 15-minute splash with a gray seal named Ike and a young model dressed as a mermaid. Onlookers laughed and cheered and, less than a month later, the Aquarium opened its doors on August 8, 1981, beginning the next phase of Baltimore’s urban revitalization.

As the National Aquarium celebrates its 35th anniversary this week, it’s standing on the edge again. As the interests and opinions of its visitors continue to shift away from aging point-and-look exhibits and traditional captivity methods, the Aquarium must follow the example of its original champion and commit to evolving as the city does.