Before modern technology, lighthouses were the primary way to get mariners into harbor safely.
Lighthouse keepers had to turn the light on at sundown and off at sunrise - no exceptions.
The automation of lighthouses from the 1970's onward meant many of the state's beacons were demolished or fell into disrepair.
But thanks to local efforts like that of the American Lighthouse Foundation, some of these lights have been restored.
Headquartered at Owls Head Light on Penobscot Bay, the non-profit was started in 1994 with the sole mission of saving lighthouses.
"it's important to preserve these lighthouses because we won't build them again," said Bob Trapani, the executive director of the American Lighthouse Foundation. "You do not have to be a lighthouse enthusiast to love lighthouses. There's a romance about them, there's a mystery about them."
Owls Head was built in 1825 to guide ships coming into Rockland Harbor. The original structure didn't hold up well and was rebuilt a couple decades later.
In 1980 the light was automated, and for years used as housing for the Coast Guard.
The American Lighthouse Foundation took over in the 2000's and takes care of the lens of Owls Head Light, one of eight of its kind still left in Maine.
The keeper's house and the grounds are now open to the public. And staff said they see about 125,000 people a year.
"The big thing is we're still making history with these lighthouses, just in a different way," said Trapani.
Now Owls Head Light serves as backup navigation to GPS, and mariners can activate the fog horn signal from their own boats.
But in the 1930's, it was the light keeper's dog who was trained to go up into the fog bell tower and yank on the rope with its mouth.
"Spot" the Cocker Spaniel is credited with saving the Matinicus mailboat in a snow storm.
Spot could not get to the fog bell tower because of the bad weather, but started barking so loudly, the captain heard him and turned around. A plaque at Owl's Head today still marks the close save thanks to man's best friend.
Owls Head can be accessed on land, but as you head Downeast into Maine, the lighthouses get harder to get to.
On a remote island, miles off the coast of Cutler, is Little River Light.
Once listed as one of the ten most endangered historic properties by Maine Preservation, the light was scheduled for demolition.
"Nobody wanted it," said Tim Harrison, the editor and publisher of the magazine Lighthouse Digest, "you know the lighthouse was offered to the state of Maine, it was offered to the National Park Service, but every government agency said that the lighthouse was too remote."
Starting in 1998, Tim Harrison, who started the American Lighthouse Foundation, and other volunteers not only raised $250,000 to restore the light, but did the hard work themselves. Something made more difficult because they had to put in a boat ramp and temporary dock just to get in supplies.
By the fall of 2001, Little River was ready to be re-lit for the first time in decades. But the terrorist attacks of 9/11 delayed that ceremony.
"As I was watching television, President Bush came on television to speak to the nation and mentioned that night that America was targeted and attacked because we're the biggest beacon of freedom and opportunity in the world, and no one will keep that light from shining," said Harrison. "And I thought after I heard him say that, that's it."
So about four weeks after the attacks, in what Harrison called the biggest event the small town of Cutler had ever seen, Little River was re-lit as a beacon of freedom in honor of the 9/11 victims.
That light is still on today, thanks to the American Lighthouse Foundation. Now Little River is open in July and August for overnight stays and private events.
Coming up in part two - hear from a 90-year-old Mainer, who was a lighthouse keeper for four of the state's lights.