About 10 miles offshore from Boston on a tiny rocky island sits the Boston Light. During the course of its service, the simple stucco lighthouse has welcomed everything from Revolution-era warships to massive modern shipping liners into the Boston Harbor. Now, as America’s oldest-operating lighthouse, the Boston Light is celebrating its 300th year of operation.

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When the Boston Light was first lit in 1716, the world was a very different place: the American revolution was almost five decades away, ships took months to cross the Atlantic Ocean and the lighthouse guided them into the harbor using just a simple flame and a lens. Nowadays, the Boston Light shines out into the night using a massive brass and glass lens that looks more like a sculpture than a lightbulb and is run by computers. One thing has remained the same though, it still needs a lighthouse keeper, Cara Giamo reports for Atlas Obscura.

The current one, Sally Snowman, said that the place speaks to her in an interview with Justin Shatwell for Yankee Magazine in 2009.“I grew up in the harbor, and I was always fascinated by Boston Light,” Snowman said. “When I was 10 years old, my dad brought me out here, and I fell in love with the place. I never thought that someday I’d be a lighthouse keeper out here.”

Snowman is the 70th keeper who has taken charge of the Boston Light, and she’s the Coast Guard's last resident light keeper. Thanks to advancements in navigational technology like GPS, the Coast Guard spent decades decommissioning many of the iconic lighthouses that are scattered throughout the coastal waters of the U.S. However, Snowman says her job is still as important as ever.

"There's so many pleasure boaters and small boats and fishermen and lobsterwomen and things like that that still depend upon that visual sighting," Snowman tells Deborah Becker and Kassandra Sundt for WBUR. "So, although vessels have electronics, they have a tendency to fail, and they're going to want to go to that chart, that paper chart, and they're going to want to figure out where they are."

While a lighthouse has kept watch from this island for centuries, technically it’s not the same building. The original lighthouse was destroyed by the British at the start of the American Revolution in 1776, and the current structure was rebuilt on its foundations in 1783. Since then, the Coast Guard (which owns and operates the country’s lighthouses) has upgraded the building with electronic equipment that keeps the light going despite its age, Giamo writes.

Thanks to the Boston Light’s historic significance, the federal government has kept it staffed despite most ships’ reliance on newer technologies. These days, Snowman lives out on the island from April to October, where she runs a little museum and gives tours to curious visitors in addition to keeping the lighthouse in working order. However, she still gets frantic calls in the middle of the night if nearby residents notice that the light is out—though usually she'll already know about it.

“Because it's an 1859 optic, and we're in 21st century electronics, there's glitches for the two centuries to talk to each other,” Snowman tells Becker and Sundt. “So it's not infrequent that the light is out.”

Lighthouses may be a thing of the past, but thanks to Snowman, the Boston Light is still shining strong.