For worldwide coverage ViewRanger can also display online OpenStreetMap, OpenCycleMap, Bing and Bing Aerial Imagery charts. This mapping is hosted online and downloaded to your phone as it is needed. You can cache it to your phone temporarily to use in offline mode (i.e. without mobile network coverage). Because it is free its level of details may vary around the world. Our wiki has more details
You can add detailed topographic mapping (and for some countries other charts such as VFR charts). We work with national mapping agencies and cartographic publishers around the world. The maps below indicate where we have Premium map content available.