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) New World (Biogeographic realm) Nearctic "terrestrial ecoregions" (Nearctic) (Ecoregion complex) Alaskan North Slope Coastal Tundra (Nearctic) (Terrestrial ecoregion) Arctic foothills tundra (Nearctic) "Alaska" (Arctic foothills tundra)