Visitors to New York's American Museum of Natural History are not likely to forget their first encounter with the giant blue whale suspended from the ceiling of the Museum's Hall of Ocean Life. But the beloved, 30-meter long icon was anatomically incorrect until a recently-completed renovation to the model, part of the entire Hall's refurbishment, put things right. The renovated exhibition hall, like the whale, better depicts the undersea world, and better reflects the Museum's dedication to conservation.

After a two-and-a-half year renovation, the Hall of Ocean Life has never sounded, or looked, better. For many of the Museum's five million yearly visitors, it's the closest thing to a dreamy descent into the ocean's murky depths available on dry land.

The renovation is the first since the great blue whale was installed in the mid-1960s. According to Museum curator Melanie Stiassny, change was long overdue. "It was a great hall. But in many ways, it wasn't really telling the story of the ocean. In the intervening 30 years, we have learned a tremendous amount about the oceans, the oceans as the motor of life for this planet," she says.

Construction on the Hall of Ocean Life began in 1922 and it finally opened to the public in May 1933. Ms. Stiassny says the original hall reflected the 19th century concept that nature served man, focusing on the whaling industry, and activities like pearl-diving. A diorama depicting Pacific pearl divers still stands.

Now, Ms. Stiassny says, the updated exhibition reflects the public's increasing reverence and respect for ocean life. But, she says, the hall would have to be updated daily to keep up with the pace of discovery that marine biologists maintain. "Fish, you would think we know pretty well. They are kind of big. How many new species are we describing each year? Over 200. Every single year. We're talking vertebrates, there. We're discovering new species of whale, for heaven's sake," she says.

The ceiling of the Hall of Ocean Life was once crowded with whale skeletons, models of porpoises, and a giant squid. But the giant blue whale model muscled the others out as part of a mid-1960s renovation, and has reigned there since.

Based on a female found in 1925, the aluminum and fiberglass model weighs 10 tons, a fraction of the 200 tons the whale herself would have weighed. Ms. Stiassny says the model's designers were aware of this inaccuracy, but oblivious to many others. "In 1969 when that whale was put in, we'd walked on the moon, but we knew virtually nothing about the biology of a living blue whale, the largest animal that's ever lived on our planet. Its eyes were wrong, almost like a hammerhead shark out on big fleshy protuberances. It didn't have a belly button. It had the anatomy of its blowhole wrong. It had a real makeover," she says.

The whale is surrounded with a dizzying collection of similarly updated material, 750 sea creature models, high-definition video projections, interactive computer stations, and 14 renovated life-size dioramas, including elephant seals on Mexico's Guadalupe Island, an Arctic polar bear, and a dolphin feeding frenzy.

Much of the research that informed the new installations is funded by the museum itself, which is deeply involved in conservation projects.

The Museum's Howard Rosenbaum studies whales in the wild, and participated in the blue whale model's cosmetic surgery. He says that blue whales, in many places, have recovered from years of intense whaling, but that not all whale species are so lucky. "It's highly variable. Some species are showing signs of recovery, some are doing very well. Other populations, like the North Atlantic Right Whale, show no signs of recovery. There are only 350 individuals left," he says.

Like Ms. Stiassny, Mr. Rosenbaum stresses that, although science knows much more about the ocean today than it did 30 years ago, only five percent of the ocean, which occupies two-thirds of the earth's surface, has been explored.

Indeed, the sea continues to keep science on its toes. One of the featured fish in the hall is the Indonesian coelacanth. Western science thought the fish went extinct 70 million years ago. One was discovered, very much alive, in 1998.