This is something that every Mainer should do, but do it soon!.

Just across the Penobscot River from Bucksport, the town of Prospect is home to the historic Fort Knox. Built between 1844 and 1869, it was the first fort in Maine built entirely of granite, most previous forts used wood, earth, and stone.

The Fort Knox Historic Site and the Penobscot Narrows Observatory Bridge, will opens up to the public for the season, at the beginning of each May, and wraps up at the end of October. Both make for a really fun day of exploring for the whole family, not to mention of near perfect view of the fall foliage in the area.

The final chance to visit for the 2023 season, will be on Halloween Day, Tuesday, October 31st, so make your plans now!

The grounds will be open daily during the offseason from 9 am to sunset. Dogs are welcome if they are on a 4'-6' leash, cleaned up after and not a nuisance to other guests.

The Penobscot Bridge and Penobscot Narrows Observatory, is one of the coolest experiences you can have in the state of Maine. It is the first bridge observation tower in the United States and the tallest public bridge observatory in the entire world.

The tower reaches 420 feet into the air and allows visitors to view the bridge, the nearby Fort Knox State Historic Site, the Penobscot River, and Bay, with spectacular, mind-blowing 360-degree views. In fact, believe it or not, it is taller than the Statue of Liberty! The PNO is the tallest bridge observatory open to the public in the world. Visitors to the observatory ride Maine's fastest elevator all the way to the top.

Check out the Fort Knox webiste for more information, or give them a call at 207-469-6553

25 Ways You Can Spot a Tourist in Maine

Do you think you can spot a tourist in Maine? Here are 25 ways to know for sure.

More From WBZN Old Town Maine