Celestial (SB cantos 1 - 6)
Srimad-Bhagavatam
SB Canto 1
SB 1.11.11, Purport:
The Nāgaloka planet is situated below the earth planet, and it is understood that the sun rays are hampered there. The darkness of the planet is, however, removed by the flashes of the jewels set on the heads of the Nāgas (celestial serpents), and it is said that there are beautiful gardens, rivulets, etc., for the enjoyment of the Nāgas. It is understood here also that the place is well protected by the inhabitants. So also the city of Dvārakā was well protected by the descendants of Vṛṣṇi, who were as powerful as the Lord, insofar as He manifested His strength upon this earth.