Hashigo-nori is a Japanese form of acrobatics performed at the top of a bamboo ladder. It evolved out of Edo period firefighting techniques, where is was necessary to signal to a ground crew the location of a fire amongst tightly-clustered wooden houses. Performances are still popular at Matsuri (festivals), particularly in summer.

The ladders are only supported by hooked wooden poles, formerly used to pull down burning houses to prevent the spread of fire. Safety seems to depend on knowing what you are doing and having a good team on the ground. (It looks somewhat like a safety manual of what not to do on a ladder.)

Not the best of pictures, but they were taken at a distance in the fading twilight.