This dead-end street into the valley Onsernone is great for small and agile bikes. The road ist twisty with a lot of blind spots, but theres always room enough to cross paths with a car or even a bus (yes, theres even a public transit bus going up there).
The surface is awesome most of the time, but its possible to have some fallen rocks on the street.
The only traffic is by the locals, so this is truly a challenging but rewarding ride.