Aerial of Fort Jefferson on Garden Key, part of Dry Tortugas National Park. The park is located at the farthest end of the Florida Keys, closer to Cuba than to the USA mainland. NPS says, “To reach this remote ocean wilderness one must travel by boat or plane over 68 nautical miles of open sea.” Garden Key is the second largest island in this chain. Photo #1 by National Park Service

This astronaut photograph highlights three islands in the group: Bush Key, Hospital Key, and Garden Key, which is the site of Fort Jefferson. Fort Jefferson is a Civil War-era fort, perhaps most notable for being the prison of Dr. Samuel Mudd, who set the broken leg of John Wilkes Booth following Booth’s assassination of President Lincoln. Photo #2 by NASA ISS

The moat and turquoise crystal clear water at Dry Tortugas (DRTO) National Park. Photo #3 by Matt Kieffer

There are more than 200 historic shipwrecks at Dry Tortugas, making it a hot spot for divers and underwater archaeologists. Photo #4 by Brett Seymour via NPS

The 100-square-mile Dry Tortugas National Park has a pristine subtropical ecosystem, including an intact coral reef community. It contains important populations of fish and wildlife, including loggerhead and green sea turtles, sooty terns, frigate birds, and biodiversity of many others. It’s also an important park for underwater archaeology. Photo #5 by Brett Seymour via NPS

Diving the amazing underwater world of Dry Tortugas, which according to NOAA, “is known for its extensive coral reefs, fish, sharks, lobsters and other marine life.” Photo #6 by zavtra33

Ghost crab in front of Fort Jefferson, DRTO, Florida. Photo #7 by James Good

Aerial view Loggerhead Key, the largest islet in the Dry Tortugas. It has the 150.9 feet high (46 meters) Dry Tortugas lighthouse. Loggerhead Key island has the highest elevation in the Dry Tortugas, at 10 feet (3 m). Photo #8 by NPS

DRTO National Park preserves Fort Jefferson which was built in the 1800s. Back then, a ship sailed an average speed of about 5 mph which means it took about four days for a shipment of bricks to arrive from Pensacola to build Fort Jefferson. Despite 30 years of construction, building of the fort was never completed. This unfinished coastal fortress is composed of more than 16 million bricks. Photo #9 by Evangelio Gonzalez MD

NPS Junior Ranger Handbook explained, “Have you wondered where the name ‘Dry Tortugas’ came from? These islands were first discovered in 1513 by Spanish explorer Ponce de Leon, just 20 years after Christopher Columbus discovered the Americas. Ponce de Leon was so impressed with the abundant wildlife in the area, that he named these islands ‘Las Tortugas’ (Spanish for ‘the turtles’). There were large sea turtles everywhere! Years later, ‘Dry’ was added to the name to warn people that fresh drinking water was scarce on these islands.” Photo #10 by NOAA

Arbutus, a shipwreck near the Dry Tortugas National Park, is about 70 miles west of Key West. Arbutus was a 70 foot work vessel that sank due to hull deterioration, but without loss of life. Although the sunken Spanish galleons cannot be seen from the air, Arbutus marks the northern edge of the treasure site. Due to its mast still above water, Arbutus is a favorite to photograph from seaplanes. Photo #11 by Brandon Burns

Moat and deteriorating walls. Fort Jefferson is the largest all-masonry fort in the United States. It was built between 1846 and 1875 to protect America’s gateway to the Gulf of Mexico, but the fort was never completed. People feared that by adding bricks and cannons could cause even more settling and put even more stress on the structure. Photo #12 by NPS / Linda Friar

Waves crashing into the little sea wall. Time, water, and weather all continue to take their toll in the Dry Tortugas. Photo #13 by greghartmann

Coral and eel. For over eight years, NOAA scientists have studied Florida’s remote Dry Tortugas Ecological Reserve. It’s “widely recognized as home to some of the most productive and unique marine resources in the entire Florida Keys National Marine Sanctuary. Researchers survey important ecosystem components like coral reef habitat and reef fish at 30 permanent research stations and approximately 55 newly established research sites throughout the Tortugas reserve, as well as in Dry Tortugas National Park and adjacent unprotected areas.” Photo #14 by zavtra33

Distinguishing architectural features of the 45-foot-high, three-level hexagon that is Fort Jefferson include decorative brickwork and 2,000 arches that run half a mile around. The uncompleted fort was supposed to house 420 guns and 1,500 men. Photo #15 by NOAA

Historic parade grounds inside Fort Jefferson. This massive park is listed as a “ghost town” and some paranormal investigators believe it’s haunted. Photo #16 by NPS

Neverending archways at the fort. Photo #17 by Matthew Paulson

The Dry Tortugas Lighthouse on Loggerhead Key, Florida, U.S.A. The lighthouse was constructed in 1858. Photo #18 by U.S. Coast Guard

Navy Lieutenant Luke Kremer pilots his F/A-18 C ‘Hornet’ strike fighter from the ‘Fighting Redcock’ of Strike Fighter Squadron Two Two (VFA-22) over the Fort Jefferson National Monument. U.S. Navy Photo #19 by Lieutenant Commander Creighton Holt

Fort Jefferson Moat and Seawall. The photographer wrote, “Yes, a moat around a fort surrounded by open sea. Once explained, it made perfect sense.” Photo #20 by Terry Tyson

Fort Jefferson Arches. The fort was in federal hands during the Civil War. After that in 1865, inside these walls the population declined to 1,013: 486 soldiers or civilians and 527 prisoners. Most prisoners were Army privates who were judged guilty of desertion. Most civilian prisoners were there for robbery. In July 1865, “four special civilian prisoners arrived. These were Dr. Samuel Mudd, Edmund Spangler, Samuel Arnold, and Michael O’Laughlen, who had been convicted of conspiracy in the assassination of President Abraham Lincoln.” Although Dr. Mudd had who set John Wilkes Booth’s broken leg after the assassination of President Lincoln, “Mudd provided much-praised medical care during a yellow fever epidemic at the fort in 1867, and was eventually pardoned by President Andrew Johnson and released.” Photo #21 by Scott (Revo_1599)

Rays of sunshine peek through the arches at abandoned Fort Jefferson. Photo #22 by BernieCB / NPS

If you come to visit Dry Tortugas, you should know there are no services on Garden Key where Fort Jefferson. No food, no drinks, no gasoline for refilling boats, no bartering. Visitors must plan ahead and bring everything they need for the trip with them and take everything back with them to the mainland. Photo #23 by Vaughan Nelson

NPS explained, “Abandoned by the Army in 1874, the fort was later used as a coaling station for warships. In 1898, the USS Maine sailed into history, departing the Tortugas on its fateful mission to Havana, Cuba. Though used briefly during both world wars, the fort’s final chapter as ‘Guardian of the Gulf’ had long since closed.” Photo #24 by Bruce Tuten

This fort “was a vital link in a chain of coastal forts that stretched from Maine to California. Fort Jefferson, the most sophisticated of these, was a brilliant and undeniable symbol that the United States wanted to be left alone. Though never attacked, the fort fulfilled its intended role. It helped to protect the peace and prosperity of a young nation.” Photo #25 by Richard Lopez

Lighthouse Keepers Quarters, Loggerhead Key. Photo #26 by Don Sampson

Brown Pelican flying over DTRO. The seaplane site states, “Just west of Key West, we fly over an area known as the ‘Flats’. This is a body of very shallow water only 3-5 feet deep, extending almost 20 miles. This area is part of the National Marine Sanctuary and is a very sensitive eco system, teeming with marine and bird life.” Photo #27 by Matthew Paulson

Fort Jefferson Mooring. NPS Did You Know states, “The islands of the Dry Tortugas are in a constant state of flux. Due to the errosive effects of tropical storms, shorelines are constantly being reshaped. In fact, entire islands have been know to disappear or reform following the passage of particularly violent hurricanes.” Photo #28 by Seamoor

Diving Dry Tortugas. Photo #29 by zavtra33

Underwater Archaeology. Documenting submerged cultural resource. Photo #30 by Brett Seymour / NPS & #31 by NPS / Brett Seymour

NPS is just one of the agencies monitoring the reef and underwater biodiversity. According to this study, “45% (13 of 29) of fish species in the park are over-fished and 62% (18 of 29) of fish species exceed the federal fishing mortality target by two to six times. The study also concluded that the reef fishery is in worse condition inside the park than in the surrounding area.” Photo #32 by zavtra33

Key West Seaplane Charters says, “Beyond the Marquesas Islands lie the ‘Quicksands.’ This area is excellent for spotting huge sea turtles. The water goes down to 30 feet deep and you will be flying over an under water desert. The sea-bed is made up of huge sand dunes that are continually moved by the strong tidal currents. It is here that the famous treasure salver Mel fisher found the treasures of the Spanish Galleons ‘Atocha’ and ‘Margarita.’ Over half a billion dollars worth of gold and silver strewn across an eight-mile area. Today this is still an active treasure site with regular finds of huge Spanish Emeralds.” Photo #33 by C.J. Peters & #34 by MikeAdler & #35 by NPS & #36 by NPS

Cuban ‘Chug’ Boats at Ft. Jefferson. Built in secret from collected materials, these small homemade boats travel approximately 90 miles from the coast of Cuba to Dry Tortugas National Park and other points along the southern Atlantic and Gulf coasts of the United States. Cuban refugees seeking a new life in America travel many hours or even days in hopes of reaching the U.S. soil. Photo #37 by Seamoor

Naval Air Station (NAS) Key West’s UH-3H Sea King helicopter flies near Fort Jefferson in the Dry Tortugas National Park off the southernmost tip of Florida during its last flight. The Sea King was transferred to NAS Pensacola, Fla., after it serving as NAS Key West’s search and rescue helicopter for almost a decade. At the controls for the last training flight were Lt. Gainey Maxell and Lt. Tony Martinez. U.S. Navy Photo #38 by James Brooks

Aerial, by sea and Light House at Dry Tortugas. You can reach DRTO by private boat, by public ferry or by seaplane. Many people come here for snorkeling, observing the underwater wildlife, vibrant coral, or to see the submerged shipwrecks. Photo #39 by Karen Hoffmann & #40 by Don Sampson & #41 by vladeb

According to Wikipedia, “Flashback by Nevada Barr (2003) takes place entirely on Fort Jefferson. The mystery shifts between the site as a contemporary national park and as Fort Jefferson during the post-Civil War era. Some scenes for the 1997 made-for-TV movie, Assault on Devil’s Island, were shot at Fort Jefferson.” Photo #42 by Bruce Tuten

Fort Jefferson (Garden Key) Lighthouse with full moon. A lighthouse was one of the first priorities for safety since “the Dry Tortugas have been the site where hundreds of ships have wrecked, stranded, or sustained causalities since its discovery in 1513.” This lighthouse was built in 1825. Photo #43 by Matthew Paulson

Loggerhead Key Lighthouse Sunset “taken from Fort Jefferson on Garden Key at 400mm.” Photo #44 by Matthew Paulson