The Caminito del Rey is a timber boardwalk one metre wide, bolted to a vertical cliff in the Gaitanes gorge of Málaga province, southern Spain, 105 metres above the river. There is nothing underneath it but air. Rock brushes your shoulder on one side, the drop opens off the other, and the hollow knock of your own steps is the loudest sound in the gorge. Down through the boards, the path it replaced is right there, a metre below: cracked slabs, floors missing altogether, rail ends hanging out over the drop. That one was built between 1901 and 1905 for the men working two hydroelectric plants, and took its name when Alfonso XIII walked it in 1921. Then it fell apart. The province sealed it in 2000 and demolished the first stretch. People climbed in and crossed what was left anyway, filmed it, and a ruin nobody was allowed on became famous worldwide as the most dangerous path there is. That reputation, earned while it was shut, is why most people have heard of it. The boardwalk above it opened in 2015.
The walk runs 2.9 kilometres along the wall. At its tightest the Gaitanejo closes to less than ten metres wall to wall and the sky thins to a strip. Green water grinds through the crack below, and the sound comes back up doubled. Where the cliffs stand closest, a thirty-five-metre suspension bridge crosses the void, giving a little under every step you take. Between the two canyons the path leaves the rock for open pine forest, limestone towers standing over the trees. This is the stretch where people finally take their eyes off the edge. Engineers had the gorge long before any of this. The Málaga–Córdoba railway opened in 1865 and needed seventeen tunnels and a run of bridges, several bunched here. Trains still cross at almost your height, out of one cliff and into the next. Beside the planks, plants are rooted in nothing but a crack, and on the ledges just above, griffon vultures lay their single egg straight onto bare stone.