This document discusses the science of human walking and its benefits. It explores how walking first evolved in the sea over 420 million years ago based on genetic studies of sea creatures. While walking was long thought to have originated on land, many bottom-dwelling sea animals actually walk along the ocean floor. The document also examines the cognitive and health benefits of walking, such as increased creativity and reduced dementia risk, and argues that cities and towns should be designed to make walking easy, accessible, safe, and enjoyable for all.