Planito is your browser for planet Earth (and others). It is lightweight yet powerful and highly extensible online and offline multi-layered viewer for aerial imagery, maps, placemarks and other geospatial data layers for Earth, Moon and other planets.
In its simplest form Planito can be used as online and offline viewer for maps from OpenStreetMap project and satellite images. But there are many more layers available with interesting and useful data for travelers, students and teachers, scientists. Thanks to extensible architecture and seamless updates, more and more layers are becoming available to existing and new users.
Source code on GitHub