Europe. Blue Marble: Next Generation cloud-free true-colour image centred on Europe. The seabed depth varies from shallow (light blue) on the continental shelves, to deep (dark blue) in the ocean basins. Landcover data is from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Terra satellite. It is taken from monthly data collected over a one year period. Behind the Earth is a skymap from the Tycho and Hipparcos star catalogues.