Sarah Sekula

Special to USA TODAY

After a 2 1/2-hour boat ride, it finally comes into focus: an enormous fort in the Gulf of Mexico that seems to rise up out of the water. Beneath it: a tiny island known as the Dry Tortugas.

Kristen Marks is giddy with delight. Not only is she checking another national park off the list, she is also visiting a place that not many people ever get to explore. With only about 70,000 annual visitors, Dry Tortugas National Park, about 70 nautical miles west of Key West, happens to be one of the least-visited national parks.

Why? For starters, it’s tricky to get here. The options include a long ferry ride, a 30-minute seaplane flight or going by private boat. In other words, it’s a remote spot in the middle of nowhere.

But that’s exactly its appeal.

“It's an effort to get there, but you will be rewarded with amazing views, compelling stories and the feeling of really escaping it all,” says Allyson Gantt, acting chief of public affairs for the Everglades and Dry Tortugas national parks.

Once your feet touch the sandy shores, the best way to while away the day is to take a dip. After all, nearly 99% of the park’s hundred square miles is submerged beneath the picturesque waters. With an amazing coral reef system and loads of sea critters like moray eels, Goliath grouper and candy-colored fish, it’s easy to spend hours flipper-kicking your way around.

Not to mention, there’s a very good chance you’ll see turtles. Juan Ponce de León did name this archipelago Las Tortugas, after all, when he discovered the islands in 1513. It’s not uncommon to spot loggerhead, green, hawksbill and leatherback turtles. When explorers found out there was no fresh drinking water around, they renamed it Dry Tortugas.

Step back in time

Like many travelers, Miami resident Joseph Nunez didn’t know a whole lot about Dry Tortugas before visiting. “My first impression was that Fort Jefferson could easily be one of the modern wonders of the world,” he says. “It’s insane to think there is a huge fortress out in the middle of the ocean, especially considering that it’s been there since the 1800s.”

In fact, the Civil War-era landmark is one of the largest 19th-century forts in the nation.

“To me, this place embodies all that our national parks preserve,” says Gantt. “Nature and history are equally represented here, as well as the challenges of preserving and protecting that which we value.”

If camping is your thing, this island makes for a pretty epic place to park your tent. “Visitors can camp right near the beach, outside of the fort,” says Gantt. “The designated camping area has sandy ground and some shade trees. The night sky and the sound of water lapping nearby make for a special experience.”

Just keep in mind that the campsites get booked months ahead of time.

“You feel lucky and fortunate to be able to have visited a place so timeless,” Marks says. “It feels as though you were transported to another world and another time.”

Key West: More than Key lime pie

For Marks, as with most travelers, her trip to the Dry Tortugas was a day trip during a vacation in Key West, which she says was the perfect launching point for adventures galore.

The Florida Keys have been a welcome respite to sun-loving travelers since the 1930s. With beautiful beaches, live music and adorable pastel-colored bungalows, it comes as no surprise that the southernmost key was Ernest Hemingway’s muse. It was on this tiny island surrounded by turquoise water that he pumped out some of his most prolific prose.

These days, the Ernest Hemingway Home & Museum is a National Historic Landmark where you can take a tour, snap photos next to his typewriter and say hello to the famous six-toed cats. Dozens of them roam the lush, 1-acre property. You’ll see them playing, eating or lapping up water from the fountain. And it’s not uncommon to see one curled up on Hemingway’s bed.

For Megan Faust and her husband, who lived in Key West for 10 years, getting out on the water was the preferred method of relaxation.

“People generally feel a biological connection to water,” she says. “You are 100% mentally and physically present with your immediate surroundings; it has a way of washing your stresses away.”

If you’re itching to hop into that inviting turquoise water yourself, there are loads of impressive dive and snorkel spots, including the Outer Reef where lionfish and turtle sightings are plentiful. Or opt for a wreck dive for more of a challenge. Dive Key West takes divers to a slew of cool wrecks, including the USS Vandenberg, a missile-tracking ship used in World War II.

Prefer to skim the surface instead? Paddleboading past mangroves is always a treat and renting a see-through kayak from Clearly Unique Ocean Adventures can provide quite the show (think stingrays and dolphins darting right beneath you).

Whatever you choose, the good news is: You really can’t go wrong. Time in the Florida Keys is a surefire way to score some R&R with a healthy dose of adventure.

If you go

If you plan a side trip to the Dry Tortugas, book your transportation to the island early. Key West Seaplane Adventures is the only seaplane company allowed in Dry Tortugas National Park, and in high season they have to turn people away.

The Yankee Freedom II ferry also fills up quickly.

Pro tip: Purchase the America the Beautiful pass beforehand, and park admission is subtracted from the ferry cost.

For more information, visit nps.gov/drto.