In the 1700s and 1800s this town was a trading center for sugar, rum, and molasses. Today there are law offices, tourist shops, and restaurants, but many of the buildings, which start at the harbor and go up the gently sloped hillsides, still date from the 18th century. You can't get lost. All streets lead back downhill to the water. If you want some friendly advice, stop by the Visitor Center (53A Company St. 340/773-0495) weekdays between 8 and 5 for maps and brochures.

Large, yellow Fort Christiansvaern (Hospital St. 340/773-1460. www.nps.gov/chri) dominates the waterfront. Because it's so easy to spot, it makes a good place to begin a walking tour. In 1749 the Danish built the fort to protect the harbor, but the structure was repeatedly damaged by hurricane-force winds and had to be partially rebuilt in 1771. It's now a national historic site, the best preserved of the few remaining Danish-built forts in the Virgin Islands. The park's visitor center is here. The $3 admission includes the Steeple Building. Rangers are on hand to answer questions. Hours are weekdays 8 to 4:45 and weekends 9 to 4:45.

When you're tired of sightseeing, stop at D. Hamilton Jackson Park (Between Fort Christiansvaern and Danish Customs House) -- on the street side of Fort Christiansvaern -- for a rest. It's named for a famed labor leader, judge, and journalist who started the first newspaper not under the thumb of the Danish crown (his birthday, November 1, is a territorial holiday celebrated with much fanfare in St. Croix).

Built in 1830 on foundations that date from 1734, the Danish Customs House (King St. 340/773-1460. www.nps.gov/chri), near Fort Christiansvaern, originally served as both a customs house and a post office. In 1926 it became the Christiansted Library, and it's been a national park facility since 1972. It's closed to the public, but the sweeping front steps make a nice place to take a break.

Constructed in 1856, the Scale House (King St. 340/773-1460. www.nps.gov/chri) was once the spot where goods passing through the port were weighed and inspected. Park staffers now sell a good selection of books about St. Croix history and its flora and fauna. The Scale House is open weekdays 8 to 4:30 and weekends 9 to 4:30.

Built by the Danes in 1753, the Steeple Building (Church St. 340/773-1460) was the first Danish Lutheran church on St. Croix. It's now a national park museum and contains exhibits that document the island's Indian inhabitants. It's worth the short walk to see the building's collection of archaeological artifacts, displays on plantation life, and exhibits on the architectural development of Christiansted, the early history of the church, and Alexander Hamilton, the first secretary of the U.S. Treasury, who grew up in St. Croix. Hours are irregular, so ask at the visitor center. The $3 admission includes Fort Christiansvaern.

The Post Office Building (Church St.), built in 1749, was once the Danish West India & Guinea Company warehouse. It now serves as the park's administrative building. One of the town's most elegant structures, Government House (King St. 340/773-1404) was built as a home for a Danish merchant in 1747. Today it houses offices. If you're here weekdays from 8 to 4:30, slip into the peaceful inner courtyard to admire the still pools and gardens. A sweeping staircase leads you to a second-story ballroom, still used for official government functions.

Buck Island Reef National Monument (Off the north shore of St. Croix. 340/773-1460. www.nps.gov/buis) has pristine beaches that are just right for sunbathing, but there's also some shade for those who don't want to fry. The snorkeling trail set in the reef allows close-up study of coral formations and tropical fish. After recovering from the spate of hurricanes that started in 1989, the coral now suffers from a condition called bleaching that leaves the coral white. Exceptionally warm water in 2005 further damaged the reefs. The reefs are expected to recover, but how long it will take is anyone's guess. There's an easy hiking trail to the island's highest point, where you'll be rewarded for your efforts by spectacular views of the reef and St. John. Charter-boat trips leave daily from the Christiansted waterfront or from Green Cay Marina, about 2 mi (3 km) east of Christiansted. Check with your hotel for recommendations.