Death Valley

Isthmus connecting Main continent with Frozen Lands

The Wall, Dragon Cementery, Frozen Door

Glacier

Death Valley is the isthmus/corridor/valley created in ancient glacier, that allows people to travel from Frozen Lands to main continent countries and vice versa. It has regular shape; with some points being narrow some not, some having ceiling some not.
While crossing you are able to see plenty of Dragon skeletons or corpses, both inside of glacier, on top of it, or wedged in it's cracks.

It takes five-six hours to get from entrance to end by foot. You are able to cross it with horses, but some spots are too narrow to get through with carriage/horse chaice.
It is impossible to climb on top of it; only flying creatures can get above.

Glacier/ice

For tribes believing in Six Mothers ( Children of Six Mothers ) Death Valley is a protection given by Mothers to humans.