You won't find the answer to our Geo Quiz on a map.
We're looking for a river in the lowlands of Canada's Hudson Bay.
It seems no European explorers ever reached this river. Nor did any fur traders.
And the elders of the Moose Cree native tribe say they know nothing of the river or its whereabouts.
So if it's not on a map, does it really exist?
Well, Canadian graduate student and explorer Adam Shaolts is about to embark on a canoe trip to chart this mystery river.
If he's successful, his expedition will literally put this river on the map.
Care to name this river? Your guess is as good as ours.
Tuesday's Geo Quiz destination is a remote river in Quebec, near the southern tip of Canada's Hudson Bay.
The Again River simply doesn't appear on most maps. It's uncharted territory.
But Canadian graduate student Adam Shoalts has single-handedly explored it in his canoe in 2011. Now he plans to venture back into the northwestern Quebec wilderness area to map it.
"The objective of this expedition is to photograph each waterfall, measure the height of each one, and record the longitude and latitude of each waterfall so they can be added to relevant topographic maps," Shoalts says.
Shoalts added that one of the biggest challenges on canoe excursions (besides bushwhacking to reach the remote river, carrying 100 pounds of food and gear, avoiding confrontations with bears, and fending off swarms of mosquitoes), are the sudden chance encounters with waterfalls.
The Royal Canadian Geographical Society describes the trip as geographical exploration in the truest sense: It will change the Canadian map, something that rarely happens in 21st century exploration.
Unexplored Territory: Hudson Bay Lowlands Expedition 2011