Swanagan and his lieutenants had to figure out everything from the Georgia Aquarium's basic design to how to import live whale sharks, the biggest fish on earth, from Taiwan to Atlanta. It was a complex top-secret journey involving boats, trucks and very big aircraft. It had never been attempted, and many scientists thought it impossible.
In 2002, Swanagan and aquarium biologist Bruce Carlson stood on a vacant downtown Atlanta lot before sunrise to determine the perfect light-intensive spot for what would become the nation's largest indoor coral reef with its critical, soaring skylight. He reveled in the aquarium's early successes and was buffeted by its glaring failures, including the deaths of its original two whale sharks after a chemical bath to rid the gentle giants of gill parasites.
The aquarium is the only one outside Asia to house the huge, filter-feeding sharks, and it was designed around the 6-million-gallon tank that is home to the polka-dotted giants.
The aquarium has been a boon for what was a blighted section of downtown real estate near Centennial Olympic Park. Restaurants and hotels have sprung up around the huge, ship-shaped building. The crowds continue to pour in as the aquarium gets ready to open an 84,000-square-foot dolphin facility next year. It has become the state's No. 2 most popular tourist attraction behind Stone Mountain.
But it has also drawn its share of criticism.
Many animal-rights activists and some scientists criticize the aquarium for displaying whale sharks, which roam oceans in the wild and can grow to the size of a bus. The aquarium now has four of the big fish, which were taken from Taiwan's annual kill quota, which has since been abolished. They would have been killed and eaten had they not been purchased by the aquarium.
"I will always remember the hours we spent together —- the frustrating ones and the exhilarating ones," Marcus said in an e-mailed statement after learning of Swanagan's death.
Marcus said the aquarium this month recorded its 10 millionth visitor.
"He will always be remembered as a friend and a creator of the Georgia Aquarium," Marcus wrote.
Anthony Godfrey, the current president and CEO of the aquarium, came to work for Swanagan as chief financial officer five years back.
"Those first two or three employees had a big impact on what this place would eventually look like," Godfrey said.
The aquarium head said Swanagan will be remembered by employees for the personal touch he brought to the job. He was a divorced father of five children. They live in the Atlanta area with Swanagan's ex-wife. He married his current wife, Suzy Holley, after the aquarium opened.
"He talked about his kids all the time," Godfrey said. "We knew everything going on in their lives. And he always asked about your kids."