Chapter 2 presents the amazing variety of running waters, lakes, ponds, and wetlands found at high altitudes. These waterbodies are not equally distributed among the world’s high altitude places, but tend to be concentrated in certain areas, primarily determined by regional climate and topography. Thus, a large proportion of the world’s truly high altitude aquatic systems are found at lower latitudes, mostly in the tropics. The chapter presents general patterns in the geographical distribution of high altitude waters, and gives examples of some of the most extreme systems. High altitude aquatic systems and habitats cover a broad variety in dynamics and physical appearance. These differences may be related to, for example, water source (glacier-fed, rain-fed, or groundwater-fed streams), geological origin (e.g. glacial, volcanic, or tectonic lakes), or catchment slope and altitude (different types of peatland wetlands). This is exemplified and richly illustrated through numerous photos.