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) Hydrosphere (Earth) - layer of water
                                   (Drainage basin) Indian Ocean Basin
                                     (Drainage basin) Persian Gulf Basin (Asia)
                                       (Drainage basin) Tigris-Euphrates Basin (Asia)
                                         0.295659N0483423E (Stream) Shatt al Arab (Iraq, Iran)
                                         s1.330500N0432900E (Stream) Euphrates River (Turkey, Syria, Iraq: Al Anbār)
                                         s2.310000N0472500E (Stream) Tigris River (Turkey, Syria, Iraq: Al Başrah)