Something old, something new and many things very deep blue can be found in Marathon, incorporated as the City of Marathon in 1999. Rich in history, Marathon includes Boot, Knights, Hog, Vaca, Stirrup, Crawl and Little Crawl keys, East and West Sister's Island, Deer and Fat Deer keys, Long Pine and Grassy keys. Centered on Vaca Key, Marathon got its name from workers on Henry Flagler's railroad, who worked night and day to meet Flagler's construction schedule. The unrelenting pace had crews saying, "This is getting to be a real Marathon." Settlements on the islands of Marathon can be traced back to the early 1800s, when Bahamians established tropical fruit farms and New England fishermen inhabited the region. Crossing the shimmering waters south of Vaca Key is the Seven Mile Bridge, one of the longest segmental bridges in the world. The Old Seven Mile Bridge, running parallel to the modern span, was the final installment of Henry Flagler's Overseas Railway and a turn-of-the-century technological marvel that took four years to construct. The spirit of this trestle's past can be found on Pigeon Key, the original construction headquarters and staging area for the building of the bridge. The island's museum contains artifacts from the Florida Keys railroad era, along with models, a video about Flagler and the railroad, and antique postcards and photos depicting early life on Pigeon Key. Throughout the region, environmental attractions provide visitors opportunities to swim with dolphins, explore hardwood hammock and rainforest, stroll white sand beaches and enjoy an abundance of water sports. World-class sport fishing can be found offshore, on the reef and flats, along the bridges and in nearby Everglades National Park. Challenging the "Silver King of the Keys," the mighty tarpon, near the bridges of Marathon is a test of strength, endurance and boating skill. Snorkel and scuba dive excursions fulfill most divers' appetites. The beautiful underwater world at Sombrero Reef and the ghostly presence of the Thunderbolt - named for its sea-going duty as a lightening target - are two of Marathon's world-class attractions. Kayakers can paddle through the solitude of local backcountry waters or try the newest sport in the Keys, fishing from a kayak. Additionally, visitors can charter a sailboat, play golf and tennis, take in the theater and eat at one of the many fine restaurants that include upscale cafs and funky waterfront seafood eateries. Marathon, called the Heart of the Florida Keys, boasts homey resorts, luxury accommodations and the conveniences of a modern community, including a 58-bed hospital and plenty of shopping opportunities, while retaining the charm of its roots as a 19th-century fishing village.