San Francisco's Laughing Sal -- the gap-toothed mechanical redhead whose shrill cackle made Playland at the Beach famous -- has a new haunt on Pier 45. The stroll through Fisherman's Wharf to find her is part of the fun.

Then again, fun is what Amusing America is all about.

The museum, which opened Aug. 5, is at the end of a tourist-thronged block lined with A. Sabella's and Alioto's seafood restaurants and past sidewalk counters where aproned workers crack open heaps of steamed crabs. Sal's garish face, and her renowned gaping mouth, are painted around the entrance to the pier's converted warehouse. Walk through -- no admission here -- and meet the six-foot-tall figure who laughed wildly for decades at the city's year-round carnival by the sea, which closed in 1972.

Now Sal is greeting visitors at an exhibit highlighting world's fairs, amusement parks, arcades, baths and dance pavilions that helped shape the social landscape from the late 19th century to World War II.

Funded by corporate groups and private individuals, Amusing America was created by the San Francisco Museum and Historical Society and was co-sponsored by the San Francisco Public Library and the California State Library. Curator Ink Mendelsohn, whose career includes writing cultural history articles for the Smithsonian Institution, sifted through hundreds of archived photos. She spent more than two years preparing the project, which will remain at Pier 45 at least through the summer of 2006.

"It's cool," said German tourist Benjamin Riedel, 20, as he paused at a one-of-a-kind steam motorcycle. The rare 1912 Steam Flyer is one of the artifacts in the exhibit, which begins by emphasizing the changes that occurred when America's urban population boomed between 1880 and 1890. Workers traded farm labor for long hours in the factory. Without the pastimes of rural life in wide open spaces, families confined in crowded cities looked for amusement.

They found it at the end of transit lines. For a small fee, the first "trolley parks" offered gardens, theaters and other entertainment. Soon new technology spawned the carousel, the Ferris wheel and, for the truly intrepid, roller coasters.

Mendelsohn's meticulous research chronicles the changing face of entertainment through images, text and quotes. But Amusing America is no stodgy tutorial -- it's more like a place where the prof meets P.T. Barnum.

High on the wall next to Sal, two giant clown heads that hung in the Playland funhouse peer down. One has wiggling ears, and the other's piercing blue eyes move from side to side, gazing eerily at onlookers. Painted ponies from the 1900 Golden Gate Park carousel and a sleek red car from a 1920s Giant Dipper roller coaster are wooden relics. A glance toward the ceiling catches colorful boardwalk signs touting the Sea Beach Grille and a confection called It's It, a mound of vanilla ice cream wedged between two oatmeal cookies, then dipped in chocolate.

Paired with Amusing America is the Musee Mecanique. Originally part of Playland at the Beach, this collection of 175 antique coin-operated music and arcade machines is free to examine. But it costs a coin or two to test your strength, take your chances with the mysterious fortune teller, crank up the Wurlitzer player piano or pop into one of those impromptu black-and-white photo booths.

Two years ago Musee owner Ed Zelinsky was forced to move his collection when he lost his lease at the city's famed white Victorian Cliff House at Ocean Beach, which the National Park Service has acquired. Disneyland tried to woo the antiques away, but Zelinsky found a home for them on Pier 45.

"This is a unique entity that all factions of the city agree on," San Francisco native and on-site manager Neil Diggins said. "Everyone gets to be young again when they're here. They leave filled with joy."

Large north windows flood the narrow building with light and frame a scenic view of the Golden Gate Bridge and Alcatraz. You can watch as freighters move slowly through the water and small boats with puffed-out sails skim past.

The way the setting enhances the exhibit, and the enthusiastic response of visitors who have ventured in since the opening, please Mendelsohn. "I was very concerned about the total environment," she said. "I wanted to incorporate the smell of the wharf and the light from the windows and views of the bay."

The experience is likely to remind visitors of childhood treks to amusement parks, especially those in boardwalk towns where surf and saltwater taffy reigned. It's no more than an illusion, but life inside the Pier 45 museums seems to be -- at least briefly -- a cotton candy world.

-- Christine Vovakes

Amusing America and Musee Mecanique are on Pier 45 at the end of Taylor Street in San Francisco's Fisherman's Wharf. The museums are free and open daily from 10 a.m. to 8 p.m. Information: 415-775-1111,

Laughing Sal, a six-foot mechanical redhead, and a giant clown head from a funhouse are on view at San Francisco's new Amusing America museum.