At the edge of a trail in Germany’s picturesque Black Forest region, waterlogged steps sink into ankle-deep water and mud, requiring careful footing. An ocean away, a sandy trail in the ponderosa forests of northern Arizona demands treading just as deliberately when walkers reach a line of tree stumps arranged as stepping stones.
The pathways are located nearly 9,700 kilometers (6,000 miles) apart but share a notable feature: they were designed for visitors to use without wearing socks or shoes.
