Jungle Love.

The United States may have handed over the Panama Canal, but the Smithsonian is staying to promote tourism.

U.S. COLONEL GEORGE GOETHALS wasn't thinking about flora and fauna when he ordered the Panama Canal built to retain the maximum amount of surrounding jungle. But the howler monkeys and the hummingbirds--not to mention the scientists and naturalists who flock here to see them--have reason to thank him.

What Goethals had on his mind 90 years ago was security. He thought the scarcely penetrable tropical vegetation was the best protective barrier to keep any enemy troops away from the canal, construction of which was then drawing to a close under his leadership. Missiles and aircraft soon altered the military equation. But the jungle still crowds in as thickly ever, and now it is becoming the axis of a burgeoning environmental tourism strategy.

The ships of the world that chug slowly across the isthmus are passing through one of the richest areas of biodiversity in the world--Panama has more bird species than the United States and Canada combined. When Goethals and his engineers flooded an area the size of Barbados to form Gatun Lake, across which the canal passes for half its length, the species of this area could only flee to mountaintops that soon became islands.

As early as 1923, one of these now isolated hilltops, Barro Colorado Island, was chosen as a site for a biological reserve. The island--which claims more plant species in its 1,500 hectares than exist in all of Europe--became one of the first protected tropical forests in the Americas. For more than 50 years it has been under the care of the Smithsonian, the famous Washington, D.C.-based institution. In 1966, the Smithsonian Tropical Research Institute (STRI) was created in Panama.

So, while U.S. troops have left Panama and the canal itself is in Panamanian hands for the first time, the Smithsonian has stayed. According to Laura Flores, a former deputy foreign trade minister of Panama and now the institute's director of business initiatives, it is seeking ways to become more involved in supporting the local tourist industry. "This office is a new way of interacting with the community, specifically the eco-tourism business," she says, including forming new partnerships with tour operators using the Smithsonian's scientific know-how. "They want quality input into their products. You cannot just show people a forest. You have to tell them what is happening there, add value."

Mecca for science. The institute's crown jewel remains Barro Colorado Island, or BCI, which has five species of monkeys, 60 species of bats and some 100 species of cockroaches. The Smithsonian's tours of the island are restricted and highly prized: Only around 4,000 visitors get to make the guided trip around its jungles every year. "BCI is first of all, and will always be, a research station," Flores says. "That is the main asset and why people come from all over the world. It is a mecca for science."

Eco-tourism companies make trips around the island's 48 kilometers of coastline and across nearby jungle peninsulas. Flores has redesigned the visitors center and is even thinking of offering tourists more opportunities to talk to the expert scientists, who spend weeks at a time studying life on the island. "The visitor program has been increasing," she says. "We are exploring alternatives for improving access to BCI without disturbing the research that goes on."

Nearby, private money is already pouring into tourism ventures, all of which have their attraction in the canal's untouched jungle acres--and which are only now being exploited because the United States has completed its military pullout and left thousands of empty buildings.

Just south of Gatun Lake, for example, the Gamboa Rainforest Resort has opened, incorporating some of the colonial-style buildings that once belonged to the Panama Canal Company. And little pieces of history abound in the lush undergrowth--Manlio Vasquez, the resort's architect, explains that, swallowed by the nearby jungle, is a former U.S. telegraph station. When President Wilson pressed a button in Washington in 1913, it was here that the telegraph signal was received that detonated a retaining dam and filled the canal with water.

The Smithsonian, lending the obvious prestige of its name, has advised the resort. "We have collaborated with them in putting their frog pond together," Flores says. "They would not know how to put together that kind of facility."

Swords into plowshares. One of the most intriguing ventures near the canal is the Canopy Tower. Entrepreneur Raul Arias has transformed an old U.S. radar station, once used to monitor drug flights, into an exclusive lodge. Now it monitors different flights: Its treetop-high geodesic dome makes a perfect observation platform for bird watchers.

Sol Melia, the Spanish hotel chain, is embarking on another swords-into- plowshares venture. It is opening a hotel in what was once the School of the Americas, the notorious army academy that hosted Panama's own Manuel Noriega and other infamous Latin military leaders. And celebrated architect Frank Gebry--best known for Bilbao's Guggenheim museum--is drawing up plans to develop Fort Sherman, another former U.S. base at the Caribbean mouth of the canal.

Through all this snakes the canal itself, still Panama's No. 1 attraction. The Panama Canal Authority's main visitor center at Miraflores, the first set of canal locks near Panama City, receives 300,000 visitors a year, according to Dilsia Alleyne, supervisor of the authority's orientation services unit.

Despite its obvious selling points, the canal was never an active participant in the tourism industry. Now that Panama has taken over control from the United States, it will become so for a simple reason: For the first time, it is legally free to make a profit. Under U.S. control, the canal operated on a break-even basis.

So the PCA is preparing to build a larger visitor center at Miraflores. Alleyne's canal guides are sometimes booked to transit the canal on board some of the 300 cruise ships that make the voyage each year, explaining its wonders to passengers. Once cruise ships passed straight through the canal, now some stop in Gatun Lake, giving tourists the chance of a closer look through various tours. The potential is huge.

As Alleyne says, "We are the only canal in the area. We have some unique things to offer."