"I moved to Mare Island about 20 years ago," Fortner says. "I had no idea of the global impact of Mare Island and the amount of history that was just sitting here in the Bay Area."
When the base was officially closed in 1996, the Mare Island Historic Park Foundation was formed.
"It's our mission to let people know what happened here, the impact it had on the world and how we're trying to preserve that as well as let the island progress into the modern age," Fortner says.
According to Fortner, the best way to learn about the history is to just visit the island and take one of the foundation's official tours.
"It's about a 90-minute walking tour and you get the whole story of Mare Island told through these amazing locations and these amazing things that you can see along the way," Fortner says. "You can walk through from 1854 all the way to 1996 and you've got World War I, World War II, Vietnam, all the way back to the Spanish-American War."
Walking under the original shipyard cranes, visitors can take in the historic core where ships were once built. They can also see the USS Vallejo Memorial constructed from a Freedom nuclear submarine once built on the base.
"When it was decommissioned, we got the sail and we managed to turn it into a memorial to all the people who built and served on ships like this," Fortner says.
One of the highlights of the tour is a stop at Saint Peter's Chapel.
"A lot of people come because of the stained glass windows. We have 29 total stained glass windows. 25 of them are from the famed Tiffany Studios in New York," Fortner says.
Participants will also explore Alden Park.
"Captain Alden himself, when he was running the island, told all the sailors to go out into the world and bring back saplings and seedlings," Fortner says. "And this is one of the biggest collections of the most diverse trees in all of the country here in one park."
A visit to Mare Island is a truly unique and memorable experience.
"I don't think there are other places, frankly, in the country that have this same frozen-in-time piece of history that you can walk through," Fortner says.
For more information, visit https://mihpf.org/tours.