- Vertebrates (/ˈvɜːrtəbrɪts, -ˌbreɪts/) are animals with spinal cords and bony or cartilaginous backbones, including all mammals, birds, reptiles, amphibians and fish. The vertebrates consist of all the taxa within the subphylum Vertebrata (/ˌvɜːrtəˈbreɪtə/) (chordates with backbones) and represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described.
- Hollow Earth (Wikipedia)
The Hollow Earth is an obsolete concept proposing that the planet Earth is entirely hollow or contains a substantial interior space. Notably suggested by Edmond Halley in the late 17th century, the notion was disproven, first tentatively by Pierre Bouguer in 1740, then definitively by Charles Hutton in his Schiehallion experiment around 1774.