San Francisco  - Claude is 13-years-old and snow-white. A rare albino American alligator, he lives in the swamp exhibit at the California Academy of Sciences in San Francisco.

"He'd be dead already in the wild," remarked Stephanie Stone, the Academy's spokesperson. Claude is a star attraction at the Academy, which is one of the many magnets for visitors in "The City by the Bay."

Situated in Golden Gate Park, the Academy, which was badly damaged in an earthquake that hit the San Francisco Bay Area in 1989, reopened in September 2008 after a five-year reconstruction. It is one of the 10 largest natural history museums in the world and bills itself as "the world's greenest museum," in part because of its grass roof covering more than a hectare and containing 60,000 photovoltaic cells.

The first scientific research institution in the American West, the Academy was founded in 1853. Its history is closely linked with the California Gold Rush, which began in 1848 and transformed San Francisco from a small village into a boomtown, its population soaring from
375 to more than 30,000 in the space of a year.

Among the new arrivals were the Bavarian brothers Sigmund and Ignatz Steinhart, who became wealthy bankers and donated an aquarium to the city. It opened in 1923 as a key part of the Academy, which had moved from the city centre to Golden Gate Park in 1916 after burning down in the conflagration following the San Francisco earthquake of 1906. Several scientific expeditions after the disaster quickly replaced the destroyed collections.

Today much of the Academy is devoted to research. "This isn't a museum of dead things, but rather a living museum -- for the future," Stone said. It receives two million visitors a year, compared with 800,000 before the reopening.

Some details from the 12 separate structures comprising the pre-1989 Academy can be found in the new one: a 38,000-square-metre building that houses an aquarium, a planetarium, a natural history museum and a 4-story rainforest under one roof.

"Many San Francisco residents grew up with the Academy. They needed something recognizable," Stone explained. Among the preserved details are the bronze sea horse railings around Claude's swamp exhibit.

The academy offers guided tours during the daytime, when entire school classes arrive to do things like touch sea stars and other ocean creatures in the Discovery Tidepool or catch virtual butterflies with a virtual net.

Every Thursday beginning at 7 pm, the Academy plays host to visitors aged 21 and older with music and cocktails under the central glass roof, which is supported by a spider-web-like metal truss.

There is less hubbub in the daytime during the two-hour Platinum Behind-the-Scenes Tour to staff-only areas of the Academy. At a price of 99 US dollars, you can see things like the tank where sand is cleaned for the colony of African penguins, and the pumps and pipes of the Aquarium Life Support System.

Some of the system's water flows into the 100,000-gallon Northern California Coast tank, which contains all of the fish species living in the Gulf of the Farallones National Marine Sanctuary, an area of 3,250 square kilometres off the northern and central California coast near San Francisco.

The days of catching or killing wild specimens are long gone. The Academy cultivates the corals on display and breeds its animals. It used to pick up plenty of specimens at San Francisco's weekly Chinese market. Two snapping turtles that a curator saved from a cooking pot almost 50 years ago still live at the Academy. They share the swamp exhibit with Claude. (dpa)