This is an interesting tale of a sailor who one day woke up and discovered that the ocean had changed colour. From a formerly beautiful violet to the blue-green we're familiar with today. And how he spoke to other sailors and discovered that many had noted the same as well.
Link: https://www.youtube.com/watch?v=1gmVbwba8Xk
Now, at first I wondered about Gladstone's Colour Theory (Linked Here) - maybe in Homer's time it was a wine dark sea? What if the sailor's were all victims of the Mandala effect? (Linked Here). Or maybe - from time to time - reality resets itself and / or "reboots" - runs a different, updated program? Anyways, there is much to mull in this - how you can wake up one morning to a profoundly different world than the one you went to sleep in the night before.