We're heading for the hills for today's Geo Quiz. But watch out for falling rocks, and maybe even confused border guards.
The borders of half a dozen European countries run across some of the highest peaks and ridges of the Alps.
The high Alpine landscape is mostly covered with glaciers and permafrost.
But as climate change warms up the atmosphere, a lot of these frozen landscapes are melting.
And according to climatologist Luca Mercalli, that's causing problems.
"In many areas we change the stability of the soil. We could have rapid mudflows or landslides."
That could spell trouble for hikers. It also means problems for official cartographers in Luca Mercalli's country. They're having to redraw their country's borders -- as melting Alpine glaciers cause exposed land to shift.
So -- which country is having its borders redrawn by climate change?
We'll reveal the answer here...
Today's Geo Quiz sent us in search of a European country whose borders are shifting as a result of climate change.
The answer is Italy.
Many of the glaciers that lie along Italy's Alpine borders are melting. That's causing landslides and other changes in the region's topography.
That's forced Italy to agree to redraw parts of its borders with Switzerland and France. And in a separate deal with neighboring Austria, Italy has agreed to the notion of a moveable border.
It's a recognition that the melting in the mountains... will be causing big changes in the Alps for decades to come.