The Axenstrasse deserves a little respect before you ride it. It is a narrow road cut along the eastern shore of the Urnersee, between Brunnen and Flüelen, built in the 1860s when the canton of Uri and the canton of Schwyz decided they needed a road that did not depend on boats. Engineers blasted ledges into the cliffs, drove short tunnels through the headlands and added stone galleries wherever rocks threatened to fall. The result is a road that still feels like a piece of nineteenth-century ambition, squeezed between the mountain and the water.
The section marked for awareness is the one where the corridor is tight and the tunnels come in quick succession. Some are lit, some dim, and they change from bright sunlight to near darkness in a second, so sunglasses off before the first one. The surface can be damp near the galleries, and gravel or small rock sometimes washes onto the carriageway after heavy rain. Rockfall is a genuine risk here, and the road has been closed on occasion while crews secure the slopes. Check conditions if the weather has been wild.
It is also shared. Lorries, buses and cars use the same ribbon, though the motorway tunnel through the mountain takes most of the long-distance traffic now. On a summer weekend you can find yourself in a slow procession, and that is not a bad thing, because the views are the real reward. Through gaps in the rock you see the lake spread out below, deep and quiet, with the steep faces of the far shore coming down into it. A few pull-offs allow a stop, but use them with care and keep well clear of the carriageway.
Brunnen and Ingenbohl, two kilometres or so back, are the places for fuel and food. Along the Axenstrasse itself, services are limited, with a few restaurants and viewpoints tucked into the cliffs, so arrive with a full tank and a plan.
Keep to the speed limit, because the road is narrow and the tunnels have no room for error. Ride in the middle of your lane out of the galleries, since the corners tighten without warning, and let faster riders go by if they want to. It is not a place to race, and it repays patience.