OK, it's more a hole than a tunnel, but what a hole.
It's the old well for Upper Fort Garry, which once stood near where Main Street and Broadway are today.
There's a story that says when Métis leader Louis Riel was fleeing Upper Fort Garry in 1870 -- Thomas Scott had already been executed at the fort and Col. Garnet Joseph Wolseley's troops were on their way to put down the Red River Rebellion -- he dumped his personal papers down the well for safekeeping.
The story also says some of those papers spell out how the Hudson's Bay Company was to turn over land it controlled at the time -- a good portion of southern Manitoba, including what we now call Winnipeg -- to the Métis government.
As part of the research being done in the lead-up to the creation of the Upper Fort Garry Heritage Park, that original well has been located.
All that remains to seeing what's down there is a careful excavation of the site, including a thorough search to see if there are any papers backing the Métis claim to half a million hectares of land, much of which is along the Red River in Winnipeg.
The Manitoba Métis Federation first filed its land-claim case in 1981, saying land grants promised to Métis children in the Manitoba Act of 1870 had not been carried out. The organization wants compensation, which could end up in the billions.
The Supreme Court of Canada has agreed to hear their case.