At the base of the immense pillar, tiny Babylon was in shadow. Then the darkness climbed the tower, like a canopy unfurling upward. It moved slowly enough that Hillalum felt he could count the moments passing, but then it grew faster as it approached, until it raced past them faster than he could blink, and they were in twilight... For the first time, he knew night for what it was: the shadow of the earth itself, cast against the sky.
Ted Chiang, Stories of Your Life and Others
astronomy, beautiful, nature, tower-of-babylon