There it shines in American sunlight, sitting at the edge of Baton Rouge, its mustard steel skin concealed from view. It's the echo of R. Buckminster Fuller -- an inventor, designer, mathematician and architect who nearly died before arriving because of sadness in his heart.

If you ride the trembling elevator to the top of the state Capitol and squint into the distance, you won't find Bucky's dome. It's hidden far away, past a couple of plants on Highway 61, down Brooklawn, a two-laned road cut by rail lines.

Once there, railroad signs will warn you not to get near the abandoned structure. But the kid in you will walk right past the signs because it wants to know what's inside, wants to know whether the sound of your name will bounce off the rusting metal, wants to imagine what used to happen here for all those years.

This dome, it may make you misty. "It does have that affect on you. You fall in love with it," says James Young, who came upon it by accident a few months ago.

One architect calls the dome the only important building in Louisiana. Another secretly takes her architecture class inside, where glass from a dome within the dome is splattered across the floor.

"In the history of architecture, there are very rare moments that people invent entirely new structural systems," says Ursula Emery McClure, architecture professor at Louisiana State University. "And Fuller is one of the few inventors in the 20th century who, in fact, not only created an entirely new structural system, but also looked at it in the mindset of a designer."

In other words, she likes it. McClure even sees a day when a national architecture convention could hold a reception within the place, all those voices bouncing off the inverted metal hexagons, chattering about R. Buckminster's creation.

Most Louisianians don't know it's there, rusting slowly. But there is a movement, a nascent one, to save Fuller's dome in North Baton Rouge. Young, a freelance marketer and designer who worked to reinvent a downtown building for a Baton Rouge design firm, spent two months gathering information about the dome, hoping that he can find the money for preservation. He's even talked to the owner, Kansas City Southern Railway, which is willing to part with the building for a modest sum, maybe less than $500,000.

The problem: Young recently moved to England, which means that his dream to preserve the dome could have left with him.

The designer of geodesic domes, including the one in Baton Rouge that housed a tank car servicing and painting operation, was Robert Buckminster Fuller. He is part of the reason the dome here is important to architects and historians.

Who was Fuller? He was very nearly no one -- a man with a puffed-up name who was called "Bucky" by friends and referred to himself as Guinea Pig B.

Born to a poor family in Massachusetts in 1895, he earned a spot in Harvard University, where he believed that sons of the wealthy were shunning him. He skipped classes and was kicked out, though he preferred to say he was "fired."

From there, Fuller descended into alcoholism and despair. In 1927, at 32, he was bankrupt, discredited and jobless, all with a wife and new daughter. His first child had just died.

The despondent Fuller walked to the shores of Lake Michigan to kill himself. But before throwing himself into the freezing waters, he had a realization: his life belonged not to himself but to the universe. At that point, he began "an experiment to discover what the little, penniless, unknown individual might be able to do effectively on behalf of all humanity."

For the next 54 years, he invented, wrote and dreamed. His main goal was to solve worldwide problems by using the best technology, providing, as he called it, "more and more life support for everybody, with less and less resources."

"I think his most important contribution is that he sparked people's imagination and that he was one of the last people to talk about the future in a truly American way -- positive, utopian, that things are going to get better," says Robert Zwirn, LSU architecture professor.

Fuller's greatest invention, and the one he's most known for, is the geodesic dome, which he developed to solve the world's housing shortage.

The dome is considered the strongest, lightest and cheapest structure. Made of triangles, pentagons, hexagons and other shapes, geodesic domes now dot the planet, and the Buckminster Fuller Society estimates there are more than 300,000 around the globe. One of the most recognizable is at Disney's Epcot Center. The domes are used in the arctic because their aerodynamic shape withstands 180 mile per hour winds. They are easy to build offsite and quick to put together. In 1957, a geodesic dome auditorium in Honolulu was built in just 22 hours.

The Baton Rouge dome is among the most important because it was the world's first large industrial use of the geodesic concept. It started with Richard A. "Dick" Lehr, then project manager for Union Tank Car and now a small business consultant for the state Department of Environmental Quality.

In the '50s, Lehr was asked to build a tank car service shop. His first design was a long building that would house 33 cars end to end. Unsatisfied with the design because the cars were too far from necessary operations, Lehr worked up another configuration. "On a whim, I wrapped the cars around the parts area," he says. Then he added a circular bridge to move the cars among the service areas.

The new design caused another problem. "Now, how in the hell am I going to cover it?" Lehr wondered. His boss, Union Tank Car president E.A. Locke, had worked with Buckminster Fuller in Washington, D.C. during World War II. Fuller came to Baton Rouge to talk with Lehr about a solution. Lehr was unimpressed. "I wrote a letter to Locke that I wasn't really that impressed with Bucky Fuller," Lehr says. "I was a 33-year-old smart aleck at the time."

But Lehr came to his senses and decided on the dome as the solution. The building of the giant dome in the middle of nowhere was chronicled around the world. Fortune magazine ran a cover story on it. The local paper ran regular features on the construction, which was handled by Nichols Construction with oversight from Fuller's company, Synergetics.

Fuller spent months in Baton Rouge. "I lived with him for about six months," Lehr says. "I remember him teaching my kids how to build little models on our ping-pong table."

From the outside, the design of the dome makes it seem smaller than it actually is. Its diameter is 384 feet, making it big enough to house a baseball field. It's 125 feet high, weighs 620 tons and is 110,000 square feet. Each of the 321 welded steel hexagons weighs roughly 2 tons.

Inside the dome is another dome, and the second one surrounds a control tower that is 80 feet high. The second dome, once covered with glass, served no purpose.

"That was my flight of fancy," says Lehr. "My excuse was that it added support to the elevator shaft."

After 16 months of construction, the tank car operation opened in 1958. Lehr watched over the building of a second one in Wood River, Ill., which now is used by the makers of Budweiser for its tank car operations.

In the early 1980s, the company shuttered its tank car operations in Baton Rouge and shifted the work to Houston. Fuller died in July 1983, about the time the operations in Baton Rouge were padlocked.

The building has changed hands and now is owned by KCS Rail. A fence surrounds it but the gates are open, and people can walk right up to take a look inside.

The dome is slightly rusted inside; its bright yellow paint has dimmed to a mustard on the outside. Beautiful industrial lights still circle the inside, and the structure of the dome inside the dome -- Lehr's flight of fancy -- encircles the towering control structure.

If you shout hello, your greeting will echo for what seems like eternity. Young says that he is told the voices and sounds canceled each other when the place was buzzing with work.

McClure, the LSU architecture professor, says that the dome intrigues students, partly because the design is associated with a celebrity designer and partly because it's industrial. "They think it's pretty impressive." To her, the dome is important because it doesn't fit the pattern of traditional buildings found in Louisiana. "When you fly over the city, it's huge. You have the LSU football stadium and the dome."

Young was trying to promote the need to save it before he leaves town. He keeps a collection of articles and information about the history. He's relying on his marketing background to save a building he discovered while touring toxic waste dumps.

The area surrounding the dome isn't polluted. Before selling to KCS, Union Tank Car cleaned up. The dome and surrounding land, says Young, have been for sale for several years at an asking price of $500,000 but KCS might take less just for the dome.

The dome could be put back in commerce or could be used for public good, such as a learning center. It could even be taken apart and moved, Young says. Moving it would require breaking welding seams, says Lehr.

Top state officials want to look at the building, as do representatives of other groups. And if they do, Young would have the upper hand in a bid to walk in Fuller's footsteps and make a better world. That's because it's likely that the officials would, like Young and others, find Bucky's echo "absolutely amazing."