(CNN) -

Sure you can wear T-shirts and shorts almost anywhere you go in St. Augustine, Florida. You wouldn't be in the Sunshine State if you couldn't.

But it would be a serious mistake to write this small Atlantic Coast city off as just another sandy tourist trap.

Yes, the beaches are beautiful.

Yes, there are kitschy bars and a requisite gator farm in the area.

But this remarkable city -- the oldest, continuously populated European-settled city in the continental United States -- boasts a fascinating military history, an abundance of ornate Spanish architecture and a European-style historical district that is best accessed by foot or bicycle.

Start with a stroll down Aviles Street, a picturesque brick lane deemed the oldest street in the oldest city.

It's so narrow that locals often refer to the RVs that tourists sometimes try to squeeze through as "balcony killers." Palm trees peek their top-heavy heads out from behind European-style buildings housing art galleries, curio shops and cafes with cheerful outdoor seating.

"Best ambiance in the city is anywhere on that street," says local historian and unofficial St. Augustine guide Roger Smith.

Make sure to duck into the many small gardens tucked into courtyards and alcoves along the downtown streets. These beautiful shady respites -- often featuring moss-covered statuary and a bench or two -- are every bit as lovely as something you'd discover in New Orleans or Charleston, and they offer a moment of shelter from the Florida heat.

Next, check out the Gonzalez-Alvarez House on St. Francis Street. It is a well-restored double-level home with two coquina fireplaces and a second-level porch.

The oldest surviving Spanish Colonial home in the state, this residence has been occupied since the 1600s, and offers tourists a glimpse at how people survived in the sweltering tropical heat and of what possessions families valued most, including a crude water purification system that stands outside one of the exterior doors.

Witness the rich legacy

Not only is St. Augustine steeped in history, it's a city that is actively discovering itself every day. Nowhere is this more evident than in the ongoing excavations at Ponce de Leon's Fountain of Youth Archaeological Park.

As you walk paths lined with Spanish moss-laden oaks and tall, proud palm trees, you can imagine what famed explorer Ponce de Leon felt as he came ashore here in 1513 in search of his legendary Fountain of Youth.

Spanish General Pedro Menéndez de Avilés followed Ponce de Leon's path and founded the colony of St. Augustine in 1565 on this site where an ancient Native American (Timucua) village stood.

Today, visitors can watch archaeologists unearth artifacts, tour a detailed replica of the first Franciscan friars' Mission de Nombre de Dios and see a live 16th-century weapons display, including a daily cannon firing.

St. Augustine spent nearly 200 years under Spanish rule and served as an important defender of Spain's trade routes along the Atlantic.

One of the most impressive historical legacies of this military history is the grand Castillo de San Marcos, a masonry fort built starting in 1672 following a vicious attack by the pirate Robert Searle which left dozens dead and many St. Augustine homes, buildings and churches ransacked.

The highly fortified military installation also once housed the mighty Native American leader Osceola. Today, visitors can wander the fortress or catch a historical re-enactment of a colony battle.

The fort itself is built out of coquina, a type of rock found on nearby Anastasia Island that is formed from seashells and tiny mollusks, whose secretions form limestone. The material absorbs shock so well that cannonballs lobbed at the fort tended to bounce off the thick walls or stick in them, according to historian Smith.

Look in on an opulent era

St. Augustine's glitzy phase was ushered in in the 1880s when oil tycoon Henry Flagler, seeking a warmer climate for his ailing wife, was charmed by this curious beach town. Flagler decided to turn St. Augustine into a destination for the wealthy and famous.

Among other things, he built the opulent Ponce de Leon Hotel, a stunning example of Spanish Renaissance architecture and one of the first buildings in the nation to have electricity. The hotel's luxurious ballroom is ringed by Tiffany stained glass windows, carved wooden columns and murals painted by artist George W. Maynard.

"[Flagler] really spearheaded the idea of hotels for wealthy people from the north to spend the winter down here," says Susan Richbourg Parker, director of St. Augustine's Historical Society. "It was the Gilded Age and there was a lot of wealth. It was important for the wealthy to see and be seen and they could do that at Flagler's hotel."

Today, the Ponce de Leon is restored to its authentic origins, but it no longer operates as a hotel. Instead, the grand building serves as the centerpiece of Flagler College, and houses a women's residence hall, dining facility and security office. Public tours of the college are available from May to December and cost $10 per adult.