ST. CROIX, U.S. Virgin Islands - The blue skies over St. Croix are dotted with clouds that create just enough shadow to cut the glare of sun on water. As my little rental car wheezes up the steep, twisting road, the sea is below on my right, a deep sapphire streaked with aquamarine.

On my left, lush slopes in a thousand shades of green sweep gently up, the creep of foliage interrupted now and then by a house positioned for the best views of the water.

I'm searching for the road to Cane Bay when I come around a curve and enter what looks like a tropical rain forest. Dense trees form a canopy over the road, their trunks almost hidden by thick ferns and enormous leaves. Vines and roots dangle from branches, and it feels like the malevolent forest of fairy tales.

Finally I emerge into the flatlands, far from the sea, and it is clear that Cane Bay is somewhere behind me.

Lost again.

This is my first visit to St. Croix, and I'm finding navigation a challenge. I am disoriented by driving on the left and hampered by the lack of street signs. But I love to explore new places, and this drive, full of wrong turns and scenic distractions, is taking me to parts of the island I probably wouldn't have visited if I'd brought a GPS.

St. Croix, which has been a U.S. territory since 1917, shares the advantages of the other U.S. Virgin Islands, St. Thomas and St. John, for a U.S. traveler: no passport required; same language; same currency as on the mainland.

The island offers plenty to entertain a visitor, starting with the beaches. Cane Bay on the north shore is popular with snorkelers, and Cane Bay Wall, where the seafloor abruptly drops from about 40 feet to a depth of more than 3,000 feet, is a favorite of divers.

Buck Island Reef National Monument, a marine sanctuary just off the island's northeast shore, is part of the U.S. National Park system. Mostly encircled by a coral reef, it has one of the world's few snorkeling trails and two dive sites. Underwater markers tell about the sea life.

Salt River Bay National Historical Park and Ecological Preserve, created in 1992, offers scuba diving, snorkeling, kayaking, and hiking. It is an important archaeological site with the physical remains of three pre-Columbian cultures, as well as an important environmental site with large mangrove forests. It also has a bioluminescent bay, where microorganisms called dinoflagellates glow in the dark. I've booked a moonlight kayaking tour of the bay.

Much of the island's history involves the sugar industry. The ruins of sugar mills are scattered around, some of them incorporated into the landscaping of homes, restaurants, and resorts. Estate Whim Museum, created from a restored 18th-century sugar plantation, tells the story of its slave labor. Visitors can tour the Cruzan Rum Distillery and taste the rum, which today is made primarily with molasses from elsewhere in the Caribbean.

In the island's two cities, Frederiksted and Christiansted, I can dine and browse shops and museums.

I knew before I got here that Crucians, as island residents call themselves, drive on the left side of the street. I'm not clear why, since this is a U.S. territory, not British. Unlike in Britain, however, the driver's seat is on the left.

The first time I got lost was on the way to my hotel from the airport.

One day I decide to tour the island, to go where the road takes me. The island is only 28 miles long and seven miles wide, so how lost can I get? I'm puzzled by the lack of signage. Would it hurt to nail up a couple of signs that point east and west, to Christiansted and Frederiksted, to the turn for Road 69 or Cane Bay?

The road is lined with blooming trees and shrubs: the red-orange poinciana; pink and scarlet hibiscus; bougainvillea in pink and purple; clusters of tiny pink flowers I don't recognize. The island is mountainous, the winding road often high above the sea; the scenery reminds me of Hawaii.

I come unexpectedly upon the Divi casino, the island's only one. I like to play blackjack, and more than that, I like to observe other players. I like the laughter, the stories, the impulsive decisions, the rueful remarks. But these gamblers are serious. I move on.

One day I go to St. George Village Botanical Garden, where more than 1,000 varieties of plants grow among the ruins of a Danish sugar plantation.

From there, I go on to Frederiksted, which is where cruise ships dock. Although it is the largest of the U.S. Virgin Islands, St. Croix is not a busy cruise destination even in winter. The Caribbean Museum Center for the Arts is here. Fort Frederik, built in the 1750s to ward off pirates, and Emancipation Park are just down the street. But many businesses are closed when there's not a ship in port, and the day I visit the streets and sidewalks are mostly empty.

The streets behind the waterfront are shabby. Buildings are deteriorating, windows boarded up.

Christiansted is more inviting, although if you walk a few blocks uphill, past the shops and galleries, you encounter similar crumbling buildings. But down by the water are a boardwalk and a marina. They don't exactly bustle offseason, but neither are they deserted. There are people in the restaurants and bars, and boats sail across the harbor. A seaplane returning from St. Thomas swings low across the shore, lands on the water, taxis to a dock.

The Danes - who ruled St. Croix for 184 years, longer than any other country, and ultimately sold the island to the United States - set up government in Christiansted. Five buildings from the colonial era, including the Customs House and Fort Christiansvaern, remain on the waterfront and make up what is now designated a National Historic Site.

I wander around the park, have a hoagie at Angry Nate's on the Boardwalk, then get lost driving back to my hotel - although with each trip, I puzzle out a little more of the route.

The morning of my kayaking trip, I make a dry run to the unmarked put-in spot to make sure I can find it at dusk. Then I see the sign: This is where members of Christopher Columbus' crew came ashore in 1493 during his second excursion to the New World.

The spot's "statement of significance" as a National Historic Landmark says that it is the earliest site under the U.S. flag that is associated with Columbus, and that his crew's skirmish here with Carib Indians was the first recorded conflict between Europeans and American Indians. The landing also marked the beginning of European colonialism here.

When I return for my kayak excursion that evening, I find that I am paired with Ralph, a widower and retired business owner from the Midwest. We are equally inexperienced; like me, he has been kayaking just once before. Ralph is with family - three couples who have all pushed off from the shallows by the time we climb into the last kayak, made of a clear, resin-like material so we can see the dinoflagellates in the water.

"Hey guys," he yells as we paddle toward them, "I got a date!"

Our guide tells us about hurricanes and boats that have sunk in the bay. He talks about the native people of St. Croix and how the arrival of Columbus' ships and those of other explorers spread disease and wiped out the native population. He leads us past a bird rookery, where in the twilight, we can see dozens of white egrets nesting in the trees, looking like cotton balls ensnared in the branches.

To get to the bioluminescent part of the bay, we thread our way through a marina, then paddle against a light wind about three-quarters of a mile across the darkening water. When we return, the wind will be at our backs, making the paddling easier.

As it gets darker, we see fireworms that give off a green luminescence during mating, which happens for only two or three days around the full moon. We also see newborn jellyfish that glow a fluorescent green.

But the main attraction are the dinoflagellates, just specks of light. We drag our hands in the water and they're outlined in light, like a science fiction movie about radiation gone wrong. The light flashes around our oars each time we lift them from the water. Best of all, we look right through our clear kayak bottom and see streams of light in the water, like pinstripes of tiny bubbles running backward, our own private miniature light shows. It is spectacular.

On the day I left, as I drove to the airport, I thought about what I'd do differently if I made a return trip. I'd visit the rum distillery, stay at the same casual hotel, and find Cane Bay. Maybe I'd take the seaplane to St. Thomas for a day; maybe I'd do a different kayak tour. And then, when I looked around and realized I was lost again, I resolved to bring a GPS unit.