Gecko Feet Defy Gravity

A gecko can run up a sheet of glass, and it uses no glue to do it. Each toe pad is packed with about 500,000 hair-like setae, and every seta frays into hundreds of even tinier tips.

That splitting matters. It turns one foot into millions of microscopic contact points, each one tugged toward the surface by van der Waals forces, the faint pull between molecules that sit almost touching. Alone, each tug is nothing. Multiplied by millions, they hold the whole animal.