MARATHON -- Henry Morrison Flagler neither created nor discovered the Florida Keys.

Yet after Flagler gave his famous instructions to his railroad buiders -- “Go to Key West” -- the islands would be forever and irreversibly altered.

Enriched by a mostly successful business career capped by his stewardship of the Standard Oil monolith, Flagler in his 50s turned to building resorts along Florida’s east coast and running the Florida East Coast Railway so vacationers could reach them.

Flagler held a shipping business as part of his personal empire. The canny industrialist realized his railroad needed to reach Key West as the U.S. port closest to the Panama Canal, under construction in roughly the same timeframe as his Over-Sea Railroad.

Building a railroad across more than 100 miles of swamp, thickly wooded islands and, most dauntingly, seemingly unbridgeable miles of open ocean had occurred to Flagler years before, said Jerry Wilkinson, founder and president of the Upper Keys Historical Preservation Society.

Corporate records show Flagler raised the topic at an 1893 board meeting, three years before the Florida East Coast Railway had reached the fledgling community that would become Miami.

“How would he have that vision?” Wilkinson, a Flager re-enactor, still wonders.

Construction began on the Florida East Coast Railway, Key West Extension, in 1905. Seven years and millions of dollars later, Flagler in 1912 rode his own railcar all the way through the Keys (although final construction on the railroad would last several more years).

“The railroad connected the Keys to the mainland for the first time,” Monroe County Library historian Tom Hambright said.

“That probably never would have happened had it not been for Henry Flagler,” Hambright said. “It took his private money to do that. Who else could? No one could come close.”

Key West gave travelers a destination but the Southermost City already was known. It was the third-largest city in Florida in 1905 with a vibrant cigar industry and military installations. “Key West was a boomtown,” Hambright said.

“The railroad opened the Keys to civilization and enterprise,” Wilkinson said. “Eventually the road was going to be built, but Flagler’s railroad got a lot of the work done for the road.

“If nothing else, the raiload probably moved Keys society a step forward by about 20 years,” Wilkinson said. “Where would the water pipeline and electric lines gone, if they couldn’t hang them off Flagler’s bridges?”

Wilkinson speculated that costs of building U.S. 1 without Flagler’s advance work would have made it an expensive drive. “The highway toll would have been much higher and lasted a lot longer.”

Marathon largely evolved as a railroad work camp, later becoming a major freight and passenger port for shipping commerce with Cuba.

Hundreds of railroad cars laden with pineapples, molasses and sugar rolled off ships and onto a long railroad pier extending into the Atlantic Ocean, near what is now the 33rd Street area. Manufactured goods went to Cuba.

Fishing

By the late 1920s, Marathon pioneer William Parrish created a commercial-fishing industry by turning railroad buildings into fish houses and docking fishing boats where steamships once tied up.

Dan Gallagher, a Middle Keys Historian, said: “Best of all, there was a train to take fish to market.” The railroad hastened the demise of the Keys agricultural economy (which gave Plantation Key its name) but business already was in decline, Keys historians said.

The mainstay pineapple plantations in the Upper Keys had been hurt by a 1909-10 blight, Wilkinson said. “Cuba’s pineapples were better and cheaper,” Hambright said.

Keys farmers tried switching to winter vegetables, but farmers in Dade County beat them to it since they had new access to railroad shipping too.

“The railroad carried a lot of stuff into and out of the Keys but most of the business was with Cuba,” Wilkinson said. “There was a limit on how much the railroad could move effectively within the Keys.”

The Keys railroad enjoyed a heyday of only about two decades. The system was financially hurting before the 1935 Labor Day Hurricane destroyed the Over-Sea Railroad.

Not all predictions came true. “Flagler predicted Key West would have a population of 50,000 by 1930,” Hambright said. “It didn’t make any significant change in the population.”

Depression

The Depression and collapse of both the cigar industry and Cuban trade sent Key West’s population into a tailspin. “The local joke was that after the railroad came, it was the first good way to get off the island,” Hambright said.

Other ramifications of Henry Flager’s Over-Sea Railroad remain, a century later.

One of the first U.S. Navy air stations was built on Key West’s Trumbo Point in 1918, on land rented from the railroad. The railroad also made it easier for the military to reach Key West. “That was pretty new stuff then,” Hambright said. “Aviation was only about 10 years old at the time. So we might not have the Key West Naval Air Station if not for Flagler.”

Massive filling of wetlands and using dirt to close natural gaps between islands affected the environment. “It created big dams in places and probably caused a lot of wildlife destruction,” Wilkinson said. “We probably haven’t seen the end of the environmental effects.

“Maybe Hurricane Wilma wouldn’t have caused so much damage, if the surge had been able to flow around the islands in a natural pattern.” A major project related to the recent construction of the new Jewfish Creek Bridge was removing fill in Lake Surprise to restore natural water exchange.

But the Seven Mile Bridge and the other remaining oceanic spans from the last century also remind what can be accomplished with manual labor and primitive construction equipment.

“It was cutting-edge engineering and an incredible undertaking,” Hambright said. “There was nothing here but mud. They brought in thousands of workers every year, had to give them a place to live and bring fresh water from the Everglades.”

“Everything they needed -- equipment, cement from Germany, rock from New York -- all had to be brought in. It had to get here at the right time in an era with no cell phones or computers. It’s amazing.”