Museo de las Californias, a permanent installation at the Tijuana Cultural Center depicting the history of the Baja California peninsula, leads museumgoers on a regional time-trek beginning 73 million years ago and ending in 1935. The cultural center, known to locals as "la bola" or "CECUT" (for Centro Cultural Tijuana), is the city's largest history, science, and art museum. Once past the ticket-taker, visitors enter a dark passageway and are greeted by a lifelike Guayacura Guama, or shaman, which has been restructured from the skeleton of a Guayacura man. Each artifact or display in the exhibit is accompanied by a description in English and Spanish; this one explains that shamans were "mediators between men and the supernatural who made predictions, healed people, and conducted the clan's funerals and festivities."

Beyond the shaman is a 15-million-year-old manatee skeleton discovered in Ensenada and a miniature sculpture of an Albertosaurus, a dinosaur that inhabited the Baja peninsula 73 million years ago.

Adjacent to a mammoth's tusk and enclosed in glass atop one of the many teal-blue rectangular stands are likenesses of Guayacura and Pirucu Indian women, each in their own circular diorama. As in most hunter-gatherer cultures, the women were responsible for collecting fruits and seeds. Women from both tribes would bathe their newborn babies in urine after delivering them "because urine contains ammonia which, in small amounts, can have disinfectant properties." There are differences between the tribes. For example, Pirucu women carried their young in an oval pail on their back whereas Guayacura women held their infant in a net suspended from the carrier's forehead. In the 1700s a smallpox epidemic introduced by Europeans extinguished most of the Pirucus and wiped the Guayacuras out completely.

The History of Baja exhibit is staged on a circular path that spirals upward, past these native people and their artifacts (such as arrowheads and pottery), past a 1:4-scale model of a 16th-century ship and other items representing that period (like swords and armor brought by the Spanish and Italians), and moves toward a model of the mission of Loreto -- founded by the Italian Jesuit priest Father Juan Maria Salvatierra, who would go on to establish six other missions.

The physical pinnacle of the exhibit is a diorama of a chapel. One can walk up a few stairs and through the chapel's entrance to see pews, an altar, and original oil paintings on canvas from the 18th Century. Depicted in these paintings are the Virgin Mary, Jesus, and Saint Gertrude. Two other models, of the mission of San Ignacio Kadakaaman and the mission of San Francisco Borja, are set near a reproduction of a bell gable incorporating traditional-style bells cast in bronze.

In 1849 a series of markers were erected delineating the border between the United States and Mexico. The top of one of these markers -- Dividing Monument #258 -- is on display. A replica of a page from the Mexican Constitution, drawn up in 1857, and a replica of the Mexican Declaration of Independence, which was signed on September 28, 1821, can be viewed nearby.

Amidst these models and replicas hangs an original, tattered Juarista flag of the Mexican Coat of Arms. Though the image has undergone many transformations since it was adopted in 1821, the core elements remain the same: an eagle atop a nopal cactus, grasping a serpent with its talon and beak.

As the visitors begin their descent along the same relaxed spiral they leave the 19th Century and enter the 20th. Tucked into one area are a handful of displays highlighting the wave of Chinese immigrants who came to Mexico in the first few years of the 20th Century. During this time the United States tightened its immigration laws, and Chinese citizens attempted to cross the border clandestinely through Tijuana. Among the objects displayed are letters written in Chinese, an abacus, a cross made of antique coins, and a large, colorful dragon used as a mask on special occasions.

Antiquated machinery, such as telephones and tools, are showcased along the way and lead to artifacts from Tijuana's most memorable and celebrated casino, the Agua Caliente. Built in 1926 in the wake of the new prohibition law in the United States, Agua Caliente was a favorite destination of Hollywood stars such as Clark Gable, Fred Astaire, Rita Hayworth, Charlie Chaplin, Bing Crosby, Jimmy Durante, and Jean Harlow.

In 1935 President Lázaro Cárdenas closed Agua Caliente and prohibited gambling in Mexico. The casino-resort was replaced with five schools. A replica of the fountain that graced the entrance to the casino is on display as visitors exit this self-guided historical tour and pass under a replica of the Agua Caliente arches. -- Barbarella

Museo de las Californias (History of Baja California exhibit) Tuesday through Sunday 10 a.m. to 7 p.m. (last entrance at 6:15 p.m.) Tijuana Cultural Center Paseo de los Héroes Zona Río, Tijuana Cost: Approximately $2 Info: 011-52-664-687-9600 or www.cecut.gob.mx