Klausen Pass, Switzerland (6,391 feet or 1,948 metres at the highest point).
This runs quite close to Zurich and links Linthon (in the canton of Glarus) with Altdorf (in the canton of Uri). It is 46 km (29 miles) in length, and driving southwards from Linthon delivers you to the heart of the Swiss Alps via forest sections, switchbacks, steep slopes, tunnels and more than 135 bends.
The Pass is usually closed between October and May (due to snow).
Take care: In places there is little or nothing between you and a sheer drop into the valley below…
A spectacular drive amidst amazing scenery; usually quiet (as most through traffic uses the alternative main road).