Incredible footage shows inside secret hidden passageways that run underneath US Capitol

Viral footage has lifted the lid on secret hidden passageways that run underneath the famed US Capitol building.

The Capitol Building first started construction in 1793, so it should hardly come as a surprise the governmental building is full of history.

Despite parts being destroyed by the 1814 Burning of Washington, the building was quickly reconstructed - while the iconic central dome was added around 1866.

After a visitor centre opened in 2008, tours around the Capitol have become common - but that doesn't meant clips on hidden bits of the building aren't welcomed by those online.

Well, thankfully, North Carolina Republican representative Tim Moore has detailed secret passageways within the Capitol building in a now viral video.

He wrote on Twitter: "Come with me to see one of the hidden secrets of the Capitol!

"The Lincoln Room is one of my favorite spots to bring visitors — when President Lincoln was serving in the House, he sat by the fireplace in this room to read his letters, but the most interesting part of the room is underneath the floorboards.

"Construction started in the 1700s and there are all sorts of little hidden passageways. As you saw, I just pulled this cover up, and you can see," Moore said in the video posted to his official congressional account on Friday (May 9).

"We're just off of what's called Statuary Hall, which at one time was the actual House chamber.… But this is just an example of some of the little hidden secrets in the Capitol."

"You can see there’s a passageway. These were old stairs that used to be here but were closed off. Believe it or not, my big self [has] actually gotten down and more importantly out of this hole."

The footage has revealed secret hidden passageways (Twitter/@RepTimMooreNC)

The intriguing secret tunnels actually lead to a gateway that leads to outside of the US Capitol building, which is conveniently found below the famed Lincoln Room.

Speaking further about the tunnel, Moore said: "I’m told, and I can’t verify this …it’s one of the staircases British soldiers used when they breached the Capitol during … 1814 when they actually attacked Washington."

Over one million people have watched the video over the weekend after it offered a rare insight into life within the Capitol.

"Fun piece of history. Thank you for sharing," one person said.

While a second added: "Nobody should get any bright ideas; it is heavily guarded and cannot be entered like before."