Natura - nature actualia - actual entities Mundus Plinius - physical world Astra Plinius - celestial bodies Universe (Supercluster) Virgo-Hydra-Centaurus Supercluster (Supercluster) Virgo Supercluster (Cluster) Local Group (Galaxy) Milky Way Galaxy veter. (Spiral arm) Orion Arm (Region) Local Bubble Local Interstellar Cloud (Planetary system) Solar System (Planet-satellite system) Earth System (Planet) Earth veter. "spheres" (Earth) (Sphere) Biosphere (Earth) - zone of life "terrestrial and freshwater ecoregions" (Bioregion) Old World (Biogeographic realm) Palearctic (Desert) Sahara (Africa) (Terrestrial ecoregion) North Saharan steppe and woodlands (Palearctic) 1 "Mauritania" (North Saharan steppe and woodlands) 2 "Western Sahara" (North Saharan steppe and woodlands) 3 "Morocco" (North Saharan steppe and woodlands) 4 "Algeria" (North Saharan steppe and woodlands) 5 "Tunisia" (North Saharan steppe and woodlands) 6 "Libya" (North Saharan steppe and woodlands) 7 "Egypt" (North Saharan steppe and woodlands)