DOWNTOWN. Let someone else do the driving! You'll see all of San Antonio's sights on these trolley tours without the stress of navigating an unfamiliar city. Opt for the Grand Tour for the most thorough itinerary, or just get the short list on the Highlights Tour. A Hill Country Tour ambles down back roads, and you can even go international on the Mexico shopping tour.

DOWNTOWN. In this small historical park sits the furnished homesite of Tejano hero Jose Antonio Navarro, who advocated Texas's independence in the mid 19th century and who was San Antonio's mayor prior to that push. His restored home recreates the revolutionary period in Texas from 1810 to 1865. Important historical events are documented, and Casa Navarro interprets Texas's rich Mexican heritage using Navarro's life as a lens. Guided tours.

NATURAL BRIDGE CAVERNS. Geological activity and mineral display are something to behold, especially when you have the chance to do it up-close-and-personal. These caverns, discovered 40 years ago, take visitors for an underground glimpse of the earth's silent workings. The 140 million-year-old rock formations continually change, and every millennium, they're different ­ plan your trip accordingly. Attractions include ziplines for the adventurous and rock-panning for the landlocked, not to mention food vendors and a gift shop.

RIVER WALK. If you're tired of strolling up and down the River Walk, why not explore it by boat? Three routes ensure that you'll see everything there is to see, and knowledgeable narrators point out historic sites and dispense practical information (with a soupcon of humor). Charter tours and a more utilitarian river taxi service are also offered. While it's advisable to purchase tickets online, you can also pick them up at Rivercenter Mall, at the Holiday Inn Riverwalk, and across from the Hilton Palacio del Rio Hotel.

SAN ANTONIO. All of San Antonio's historic missions, with the exception of the Alamo, are included in this park, which was established along the San Antonio River in the 18th century. The missions stand as a reminder of Spain's most successful attempt to extend its New World dominion northward from Mexico. All missions are active parish churches and possess individual beauty. A vistor center at Mission San Jose gives the history of the missions: San Jose, for example, has had its outer wall, Native American dwellings, granary, water mill, and workshops restored. Concepcion is known for its frescoes, and San Juan has a serene chapel. Espada, the southernmost, boasts an Arab-inspired aqueduct that was part of the famous acequia water management system.