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) Saturnian System
                             (Moon) Saturn VI (Titan) C. Huygens, 1655
                               01 Albedo features
                               02 Arcus
                               03 Craters
                               04 Facula
                               05 Faculae
                               06 Fluctus
                               07 Flumina
                               08 Insulae (Titan)
                               09 Lacus
                               10 Maculae
                               11 Maria
                               12 Planitiae
                               13 Regiones
                               14 Ringed features
                               15 Undae
                               16 Virgae