You might not even have to find a really tall ladder. I know I can walk and balance just fine on a 5 cm (2 in) wide piece of wood on otherwise flat ground. But

You might not even have to find a really tall ladder. I know I can walk and balance just fine on a 5 cm (2 in) wide piece of wood on otherwise flat ground. But put me on a 5 cm wide bar over cold water, and I start to doubt my abilities to walk.