The National Museum of Natural History is home to more than 124 million specimens and artifacts, from the dazzling 45.52-carat Hope Diamond to ancient T. rex bones. But for the schoolchildren inside Elevator No. 20 near the museum's south entrance one recent afternoon, all of that could wait -- James McGrath was giving away stickers.

The six boys and girls and two adult chaperones had squeezed into the elevator on their way to the Insect Zoo on the second floor, expecting a typical step-on, step-off experience. But inside No. 20 was McGrath, with close-cropped gray hair and a shiny badge on his white shirt.

He sat in a beige seat in front of the elevator's silver-colored control panel, asked passengers their destination and pushed the button for them. Then he began peeling smiley-face stickers the size of dimes from a roll in his hand. There were giggles and laughter as the children, each 8 or 9 years old, clamored and begged for stickers in blue, yellow and red. As the door opened and the group made its way out, one boy told him, his soft voice almost lost in the chorus of thank-yous from his classmates, "You're the greatest man I've ever seen."

McGrath and his stickers spark that kind of reaction among passengers at the Smithsonian Institution's natural history museum on the Mall.

Technically, McGrath is a security officer at the museum, but he often works as an elevator operator, making sure that staff-only floors are kept off-limits to the public. Unofficially, he is a kind of public relations czar, turning what could be a dreary eight-hour job in a cramped, windowless elevator into proof of what one man can do with very little time and very little room.

Elevator operators remain one of the few living remnants of Washington's past. The late Fifine Glaws, for example, was a beloved Capitol Hill fixture on Elevator No. 5 in the Cannon House Office Building.

McGrath commands one of the busiest elevators in the nation's capital -- an automatic, pink-walled people-mover that stops on five floors inside the most-visited natural history museum in the world. Last year, the museum received 5.6 million visitors, and McGrath personally greeted a large number of them.

He's made an impression.

The museum's director, Cristian Samper, has two fish stickers on the ID cards that dangle around his neck, courtesy of McGrath. "He's the public face of the museum to many of our visitors," said Samper, who noted that his office has received calls from visitors complimenting McGrath.

Museum spokesman Randall Kremer was visiting his family in Dayton, Ohio, for the holidays once, and when friends of his parents learned that he worked for the Natural History Museum in Washington, they told him about this nice man they met in the elevator who gave their grandchildren stickers.

McGrath recently received a letter from Smithsonian Secretary Lawrence M. Small, informing him that he had been chosen one of the institution's "Unsung Heroes" for 2004. A June 24 ceremony is planned at the museum to honor the award winners.

Elevator No. 20 is perhaps an unlikely spot for McGrath, a retired lawyer from Kansas City, Mo., who lives in Northwest Washington. He won't tell his age but said he has two grandchildren and was awarded a Bronze Star in World War II. He is also the author of a self-published children's book about a blind girl, "Alice & Rachael (my friend is blind)."

"I'm 39 and holding," he said. "I got calluses from all that holding."

Some of McGrath's stickers are supplied by members of his family, who know what to get him each year for his birthday and Christmas. But most of the stickers he hands out to visitors and employees he buys with his money, spending about $30 a week. Along with stickers, he gives tourists directions and lets them in on secrets they can't find in any brochure, such as what to look for in the photo of two monkeys in a snowstorm in a ground-floor exhibit. He tells people there's a third monkey, if they look hard enough.

"What I don't understand," he said, "is how our secretary gets all the big bucks, and I'm the one having all the fun."

One day last week, McGrath sat at his post, sheets of smiley-face, lady bug and American flag stickers wedged into every crevice of the elevator's control panel and piled neatly at his feet. It was just before the lunch hour, but already his roll of 2,150 smiley-face stickers was thinning. On a slow day, he said, he hands out 250 stickers. On a good day, he passes out 800. Once, on his best day, he gave away 1,800.

McGrath is a believer in what he described as "the power of the sticker." He said he didn't realize when he first started working for the museum 12 years ago that such a small gift could have such a big impact. In McGrath's elevator, everyone gets a sticker: infants in strollers, teenage boys trying hard to look cool and senior citizens who often stare down at the blue smiley-face on his thumb, suddenly reminded that they, too, once had use for such things.

A woman in a wheelchair got on the elevator. McGrath immediately leaned in close and said to her, "You know the new rules. No wheelies." The woman smiled. Later, an elderly couple spent just a few moments inside the elevator, but by the time they left, properly stickered by McGrath and tickled by his jokes, the woman turned around and blew him a kiss.

Elevator operator James McGrath entertains hundreds of people a day at the National Museum of Natural History. "You're the greatest man I've ever seen," one boy told him.The smiles aren't limited to the smiley-face stickers McGrath hands out. Visitors compliment his manner. Young or old, large or small, everyone on James McGrath's elevator gets a sticker. On his best day, he gave out 1,800.