PHIPPSBURG -- On the first day of her summer vacation this year, Carole Harris of Auburn visited her youth.

She and her husband, Andrew, packed up their Subaru Forester and drove to Phippsburg to frolic at Fort Popham.

Harris' father used to bring the family there when she was a youngster in the 1960s. They would pack their Airsteam trailer and spend two weeks at a nearby campground.

Her father would return to Auburn to work, leaving the family free to explore the beach, the fort and all the wonders of the Popham peninsula.

"There is a magic to this area," Harris said. "There just is. I love the history of the fort, I love the beach, and I love the natural environment. It's just beautiful."

Several forts were built in what is now Phippsburg from the early 1600s to the early 1900s. Two remain: Fort Popham and Fort Baldwin.

Fort Popham was constructed in 1862, with walls of granite 30 feet tall. Crescent-shaped, it offered fortification on three sides facing the water.

Its purpose was to protect Augusta from invasion by Confederate forces during the Civil War. Outfitted with 36 cannons on tiers of casements, it offered a formidable defense -- evidenced by the fact that no enemy ever dared cross its fire.

Although never completed, Fort Popham was also outfitted during the Spanish-American War and World War I.

Nearby Fort Baldwin was built from 1905 to 1912 on a bluff overlooking the river. In many ways, it is one of Maine's forgotten forts, with relatively few visitors despite offering insight into military history and Maine's role in World War I and World War II.

Fort Baldwin consisted of three batteries with a total of five guns, ranging in size from 3 to 6 inches in diameter. The guns were removed in the 1920s, but the fort was manned during WWII with field artillery, and the military built a concrete observatory to watch for German U-Boats.

Lookouts would search the horizon for German invaders. If spotters saw enemy submarines, they would radio their location to other gun emplacements around Casco Bay.

"They'd just radio it in, and tell them where to fire. You could calculate the distance and fire as far away as Portland or Cape Elizabeth," said Tom Desjardin, a historian with the Maine Bureau of Parks and Lands. "Baldwin never fired a shot in anger. But there is evidence that they did fire. The lighthouse keeper's son on Sequin Island recalled the night the sky lit up. That was in 1943 or '44. But from where he was, the fire could have come from almost anywhere in Casco Bay."

Today, forts Popham and Baldwin are both open to the public. The state of Maine is in the process of fortifying Popham with $450,000 in bond money to work on the roof and prevent the fort's front wall from pulling away from the rest of the structure.

Visitors can roam the interior of the fort, but their movements on the rooftop are restricted because of deterioration. With the improvements, more of the second floor will be open to the public, Desjardin said. About 80,000 to 100,000 people visit Popham each year between Memorial Day and Sept. 30, when the fort closes for the season.

Because Fort Baldwin is open year-round and not staffed, it is not known how many people visit, but it's likely the number is much smaller. The fort is tucked away at the end of a narrow road, and accessible only by a short hike up a wooded trail.

A visit to either fort is like stepping into the past.

At Popham, visitors can explore dark nooks and crannies, and look out the windows of the fortress to the ocean. Depending on the tide, Gordonit's not unusual to see harbor seals feeding.

Nearby, privately run restaurants and a general store offer food and other conveniences. The beach is right there, as well.

That's why Harris and her family have been coming to the fort and the Popham area for generations. With the imagination that only a child could muster, she and her brother would peer out over the water from behind the granite-block windows to spy enemy ships approaching the mouth of Kennebec River. They would duck and hide until the ships got close, and then unload with make-believe guns to repel the interlopers.

"We probably had only ever seen that kind of history on TV. To be able to come here and experience that history in person, it was pretty exciting," said Harris, who brings visitors regularly.

The fort was part of her youth, and she wants to pass her memories on to the next generation in her family.

"There is pride of place and heritage at play here," Harris said.