In the spiritual world there are exactly the same things as we see here; namely the land, water, trees, birds, beasts, human beings, etc., and all of them are spiritual as all the varieties here are material. So these things can be understood when one is advanced in self-realization. The real form of the living entity is eternal servant of Krsna. Now this spiritual form is developed when he enters into the spiritual world.
Letter to Gurudasa, 16 May, 1970