How geckos stick to walls

Very small structures, when combined together, can have tremendous properties. Take geckos for example, they can climb vertical surfaces with apparently sticky feet. How do they do it?

A gecko has millions of hairs under each foot. The end of each hair is split into hundreds of tips, each measuring about 200 nanometers in width.

When a gecko presses its foot onto a surface of the wall, these tips unfurl and create an adhesive force that holds the gecko firmly to the wall.