Vintgar Gorge is walked on planks bolted to the cliff, a stride above the water, for its whole 1.6-kilometre length. Limestone walls 50 to 100 metres high close in on either side. The Radovna runs below them, cold with Alpine snowmelt and clear enough to show the beds of its pools, then piles into white water where the channel pinches shut. The walk ends at Šum: thirteen metres of falling water, the largest river waterfall in Slovenia, with a stone railway arch striding across the canyon just above it. Nobody had been through here at all until 1891. That winter brought so little snow and rain that the Radovna dropped away from its walls, and Jakob Žumer, the mayor of Gorje, with the photographer Benedikt Lergetporer, picked a way in. The galleries went up two years later, and the gorge opened in 1893.
The planks give slightly underfoot, and wet moss-covered rock climbs past your shoulder on one side. There is no quiet stretch: Šum simply means roar, and you hear it long before you reach it. In October the beech slopes above the walls turn, and the light coming down into the canyon goes copper. The gorge is the eastern gateway to Triglav National Park and is now run carefully. The route goes one way only, in hourly slots capped at 245 people inside at a time, and the helmet handed to you at the entrance is compulsory, because rock still comes off these walls. It opens in April and shuts for the winter after October. Most people walk out the far end and finish the day at Lake Bled.