Hiking is an outdoor activity which consists of walking in natural environments, often on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide.

Hiking is one of the fundamental outdoor activities on which many others are based. Many beautiful places can only be reached overland by hiking, and enthusiasts regard hiking as the best way to see nature. Hikers see it as better than a tour in a vehicle of any kind (or on an animal; see horseback riding) because the hiker's senses are not intruded upon by distractions such as windows, engine noise, airborne dust and fellow passengers. Hiking over long distances or over difficult terrain requires both the physical ability to do the hike and the knowledge of the route and its pitfalls.