You'll find lots to do in the Florida Keys, most of which has to do with the sea in one way or another. Go swimming or look for rare bottles on a remote beach or search for a Pink Queen Conch.

For the Kids

Your children can have an experience of a lifetime swimming with the dolphins at Dolphins Plus on Key Largo where researchers study the therapeutic relationship of dolphins to disabled and handicapped people (305-451-1993). A similar facility, the Dolphin Research Center on Grassy Key near Marathon, was once the site of Flipper's Sea School where Hollywood filmmakers shot Flipper's original movie in the 1950s. You can play and swim with the dolphins for twenty minutes for a tax-deductible contribution of $65 with a reservation. You can take a tour of the center from Wednesday through Sunday at 9:30 and 11 A.M. and 1 and 3 P.M. for a donation of $5 (305-289-0002).

The Florida Keys Children's Museum, located in the Crane Point Hammock in Marathon, offers exhibits on a tropical lagoon, a marine touch tank, a Native American chickee (hut built of palm fronds), and a historic sailing vessel. (305-743-9100)

Key Largo

Key Largo is the first of the Keys you'll reach as you drive the Overseas Highway, heading south from Florida City. Spanish explorers called it Cayo Largo, Long Island. The largest of the Keys, it gained fame as the setting of the movie Key Largo, starring Humphrey Bogart and Lauren Bacall, a film about a crime and a hurricane on the Key. Director John Huston chose Key Largo as the film's title for no other reason than it suggested some place tropical and exotic. And though he shot a few scenes on the island, he shot most of the film in Hollywood. The businesspeople of the town of Rock Harbor, Key Largo's main town, decided to change its name to Key Largo in 1952 to cash in on the notoriety from the film. But the focus here is diving, since the only living coral reef within the U.S. limits lies due east.

To get a peek at what life was like back during the farming days of the Keys, stop at the village of Tavernier at Mile Marker 92 and wander its streets. Here and there among the dense foliage you'll see old wooden houses with big shutters to protect their occupants from hurricanes.

Islamorada

You can take two 3-hour boat trips from Indian Fill Key at Mile Marker 78 to both Indian Key State Historic Site and Lignumvitae Key State Botanical Site, respectively. Boats depart at 8:30 A.M. for Indian Key and at 1:30 P.M. for Lignumvitae Key for a cost of $6 per person. You must make reservations (305-664-4815). The first tour presents the tragic tale of the once-prosperous seat of Dade County. It got to be so from the profitable salvaging of goods of reef-wrecked ships by Captain Jacob Housman, a wealthy salvager from New York. He stole one of his father's ships and sailed to Key West, looking for a piece of the lucrative salvaging trade. Not welcomed there, he purchased Indian Key in 1831 and made $30,000 the first year salvaging wrecked ships. He outfitted the 11-acre island with warehouses, a store, and a hotel and persuaded the Florida state legislature to designate it as the county seat. Unfortunately, Housman achieved his fortune through less than honest means. It seemed he used an old smuggler's trick:He'd tie a lantern around the neck of a donkey and lead him along the shore, luring unsuspecting ships onto the reefs. Eventually, he lost his salvaging license and sold the island to Dr. Henry Perrine, a botanist and physician, who cultivated tropical plants for their medicinal uses. But in 1840, Seminole Indians destroyed it and killed Perrine. Today, you can still see the wild tamarind, mango, and Mexican sisal planted by Perrine and get a feel for what life would have been like on ranger-led walks down reconstructed village streets.

The second trip takes you to the Lignumvitae Key State Botanical Site where you can learn about the forming of the Key islands. On its 332 acres stands a virgin tropical forest, which should give you some idea of what the islands looked like before humans arrived. Ranger-led walks will introduce you to unique species of plants and trees found in the Keys. One in particular, the lignum vitae, for which the Key is named, is supposedly one of the trees in the Garden of Eden, believed to be the “tree of life.” Your kids will enjoy watching the giant golden orb spiders who regularly weave their webs across the pathways. After your nature walk, you can visit the former house of William J. Matheson, built in 1919, which will show you how the first island settlers lived in the early days of settlement on the Keys. Even though the house blew away during the 1935 hurricane, workers found it and brought it back.

The Theatre of the Sea, one of the world's oldest outdoor marine parks, is the main attraction on Windley Key at Mile Marker 84.5. Though not as sophisticated as some of the newer parks like Sea World, this one allows you to touch sea lions and swim with dolphins (with a reservation). You'll also be given a raincoat to wear as you ride in a “bottomless” boat while porpoises jump before you. Admission is $11. (Open daily 9:30 A.M.–4:00 P.M., 305-644-2431)

Marathon

The area around Marathon stretches from Conch Key at Mile Marker 65 to the Seven Mile Bridge at Mile Marker 47. Besides the busy town of Marathon on Vaca Key, you'll find sights to see on many smaller islands. The first dramatic view you'll get of the area will be from the top of Long Key Bridge. It's here that the Atlantic Ocean meets the Gulf of Mexico, and it's also here that you'll feel the thrill of literally riding over the azure blue and blue-green sea. The second longest bridge in the Keys, it provides pull-off areas for your enjoyment of this spectacular scene.

In the center of the town of Marathon at Mile Marker 50 is Crane Point Hammock, headquarters of the Florida Keys Land and Sea Trust. This steamy 63-acre bayside preserve also contains tropical hardwood and mangrove forests, plus a historic conch-style house and archaeological sites. You'll also find the comprehensive Museum of Natural History of the Florida Keys within the Hammock. Here, some exhibits tell the story of pirate life on the Keys, while others display Indian and shipwreck artifacts and re-create a coral reef. Admission is $3.50 per person. (Open daily, except Tuesday, 10:30 A.M.–6:30 P.M., Friday until 8:00 P.M., 305-743-3900)

Lower Keys

Big Pine Key is the largest island in this group, second only to Key Largo in the Upper Keys. Here, you'll find shopping centers and wildlife refuges coexisting side by side. Progress seems to have been controlled here, even though there are small developments. Here, you'll experience the Keys the way they used to be in the 1940s and 1950s.

The most impressive sight is Seven Mile Bridge, which spans the sea between Marathon and Sunshine Key. This bridge replaced the original, much narrower one in 1982. Locals now refer to the former one, which Henry Flagler built in 1912, as “the longest fishing pier in the world.” From the lower peninsula of Bahia Honda Key, now a state park, you can see the structure of Flagler's original railroad bridge, a masterpiece of engineering at the time.

The 7,962-acre National Key Deer Refuge shelters tiny white-tailed Key deer, which only grow about 2 feet high, and great white herons. The best time to see the deer is in the early morning or late in the day. If you haven't visited the Everglades, you'll have a chance to see an alligator at Blue Hole, a freshwater rock quarry pond and the only one like it in the Keys. Usually, he lies just off shore waiting for prey but sometimes suns himself on the path. (305-872-2239)

One of the most bizarre sights in the Keys is the 35-foot-tall Perky Bat Tower at Mile Marker 17. No, it's not full of perky bats. Rather the contrary. It seems real estate speculator Richter C. Perky built it of local pine in 1929 to house insect-eating bats to help control the mosquitoes that plagued Sugarloaf Key. Perky, inspired by a get-rich-quick book, Bats, Mosquitoes, and Dollars, sent away for the expensive bat bait that he was assured would lure an army of bats to his tower. No bats ever appeared and the mosquitoes continued to plague the island. So Perky lost everything. Nevertheless, the bat tower still stands as a monument to ingenuity and greed.

Extra Special

The John Pennekamp Coral Reef State Park at Mile Marker 102.5 is the first underwater park in the country. Consisting of a living coral reef, it covers 2,289 acres of land and 52,722 acres offshore. Stop at the excellent Visitor Center (open daily 8 A.M.–5 P.M.) to see a giant reconstruction of a living piece of the reef housed in a circular underwater aquarium and touch tank, as well as other exhibits on hardwood hammocks and mangrove swamps. Afterward, climb the observation tower to get a panoramic view, then take the two-and-a-half hour tour on the glass-bottom boat Discovery for $12 at 9 A.M., noon, and 3 P.M. to see the actual reef. Follow this with a picnic and a swim, or fishing among the mangrove trees for trout, snook, or sheepshead, or canoeing the park's mangrove-lined inner waterways. For an extra-special treat, set sail on a sunset glass-bottom boat cruise with underwater lights.

However, the best way to see the reef is underwater. If possible, take the snorkeling tour for $20 per person, departing at 9 A.M., noon, and 3 P.M. If you're a certified diver, you can go on a guided scubadive for $30 per person at 10 A.M. and 1 P.M. You'll need to make a reservation for any of these and the glass-bottom boat tours, except perhaps in summer. Admission is $2 per car. (Open daily 8 A.M.–sunset, Toll-free 800-432-2871)

Diving is the best method for seeing many of the 650 species of tropical fish, orange sponges, purple sea fans, blue-eyed squid, coral shrimp, and spiny lobsters. Otherwise, snorkeling is the only other way to get close to the reef. Visibility is best in summer. Whichever you choose to do, you'll need an experienced guide, as the reef lies 5 miles offshore. This is a must-do experience for the whole family, no matter how you do it.

Festivals and Seasonal Events

Marathon hosts four fishing tournaments annually. Top names in pro sport fishing participate in early May for tarpon, late May for dolphinfish, early October for bonefish, and early November for sailfish.

• Nautical Flea Market: This annual Nautical Flea Market, held in February in Islamorada, offers boats, clothes, antiques, and electronics. (www.nauticalfleamarket.org)

• Marathon Seafood Festival: This food festival showcasing delights from the sea is held in March in Marathon. (Toll-free 800-262-7284)

• Florida Keys Island Festival: Islamorada celebrates life on the Keys with food and entertainment. (Toll-free 800-322-5397)

• Big Pine Winterfest: Come to a holiday fair Keys-style, held in December on Big Pine Key. (Toll-free 800-372-3722)