Imagine diving into a crystal-clear ocean and suddenly coming face-to-face with a bustling metropolis built not by humans, ...

Beneath the surface of the Southern Ocean, vast volumes of cold, dense water plunge off the Antarctic continental shelf, cascading down underwater cliffs to the ocean floor thousands of meters below.

Adult colossal squids have occasionally surfaced on fishing lines, but none had been witnessed alive in the abyss where they thrive.