This photograph shows Fort Jefferson Lighthouse, one of 30 historic lighthouses in the state of Florida. The origins of the structure go back to 1825, when a 65-foot (20-meter) tower was completed at Bush Key (now known as Garden Key) in the Dry Tortugas and fitted with a light consisting of 23 lamps in 14-inch (35-centimeter) reflectors. Construction of Fort Jefferson began in 1847. The fort covered the entire island and incorporated the lighthouse in its south wall. In 1856 a taller lighthouse was constructed, and in 1858 the Garden Key light’s lens was installed on a newer lighthouse on nearby Loggerhead Key after sailors complained that the Garden Key light was too far from the surrounding reefs to be effective. Garden Key was reduced to being a harbor light with a much weaker lens. It was damaged by a hurricane in 1873 and replaced by a new tower built of boiler plate on top of the fort’s walls, the structure shown here. Fort Jefferson was a military installation and prison that once housed the conspirators convicted of killing President Abraham Lincoln. It is now part of Dry Tortugas National Park.