Couple discovers creepy hidden tunnel under their Michigan home - before realizing fascinating reason it was dug

While a Michigan couple knew the house they bought in 2020 needed some major renovation, but they didn't expect to uncover a hidden piece of history.

Hayley Gilmartin and her husband, Trevor, were removing an old jacuzzi in their home in Lake Huron, the body of water separating the US and Canada, when they discovered a mysterious, water-filled chamber 20 feet below the surface.

The chamber, which connects to the lake via a six-foot pipe, is believed to be a Prohibition-era tunnel, which likely served as a covert route for smuggling alcohol across the border.

Haley told Newsweek the house 'was all 1970s style,' and they had always planned to remove the jacuzzi that sat in the living room. 

The couple said they knew it would be an undertaking to remove, but discovering the 'manhole like thing' underneath the jacuzzi changed everything the couple knew about the house. 

Hayley Gilmartin and her husband, Trevor, were removing an old jacuzzi in their home in Lake Huron, the body of water separating the US and Canada , when they discovered a mysterious, water-filled chamber 20 feet below the surface

The chamber, which connects to the lake via a six-foot pipe, is believed to be a Prohibition-era tunnel, likely served as a covert route for smuggling alcohol across the border

'Our house has about three feet of concrete between each floor,' Haley said.

Haley and her husband were not originally thrilled with the discovery as they found it initially unsettling.

'I think anyone finding a man hole under their house in pitch darkness is going to find it spooky,' she said. 

'But it's super clear water and nothing crazy has been found in the water.'

After mustering enough courage to see if it was safe to venture down the man hole, the couple discovered an entire other room.

'We scuba-dived in the river and found the other end of it, which is a huge tunnel,' Haley said. 

She also explained how it is 'impossible' to pump the water out of the mystery room because it 'is still getting water from Lake Huron and the rivers that it is connected to.'

Pictured: Trevor scuba diving to check out outside of the mystery room

As the couple plunged head first into the history of the house and the reason behind the room, they were bombarded with a number of theories as to what the room is actually meant for.

'We were told by people in the area that our house used to load brine onto freighters during the Second World War but not sure how accurate that is,' Hayley told Newsweek. 

'The wildest theory we've heard is that it was used in the prohibition days to smuggle alcohol over from Canada since it's so close. Although we do find many prohibition era bottles in our area.'

They also learned from several neighbors that they also have tunnels that lead to secret rooms of sorts beneath their homes.

Inside the hidden room Haley and her husband discovered

The couple learned from several neighbors that they also have tunnels that lead to secret rooms of sorts beneath their homes

The six foot pipe that connects the chamber and the lake

The other side of the wall leading to the lake/river

During Prohibition, Lake Huron and the St. Clair River transformed into bustling smuggling routes where those opposed to the US temperance movement transported bootleg alcohol from up north across the border.

Historian Douglas Bancroft said the area was the reason for 75% of illegal exports during Prohibition, he told The Times Herald.

Hayley and Trevor also found a boarded-up wooden door in the room, which they have yet to remove but plan on doing so in the future.

"We are going to keep exploring it and if possible we will drain it and maybe create a game room or bowling alley lane down there," Hayley told Newsweek.