I wouldn’t like to walk on the Caminito del Rey lol:

In 1901 it was obvious that the workers of the Chorro Falls and Gaitanejo Falls needed a walkway to cross between the falls, to provide transport of materials, vigilance and maintenance of the channel. Construction of the walkway took four years; it was finished in 1905.

In 1921 the king Alfonso XIII crossed the walkway for the inauguration of the dam Conde del Guadalhorce and it became known by its present name.

The walkway has now gone many years without maintenance, and is in a highly deteriorated and dangerous state. It is one meter (3 ft) in width, and is over 700 feet (200 m) above the river. Nearly all of the path has no handrail. Some parts of the walkway have completely collapsed and have been replaced by a beam and a metallic wire on the wall. Many people have lost their lives on the walkway in recent years. After four people died in two accidents in 1999 and 2000, the local government closed the entrances. However, adventurous tourists still find their way into the walkway.

The guys who build this walkway more than hundred years ago must have had steel balls.