A sea chart from 1539 shows sea eddies that exactly match satellite imagery, this at some surprise to modern scientists:
The ornate Carta Marina, published in 1539, appears crude by today's standards, depicting sea monsters off the coast of Scotland, sinking galleons, sea snakes, and wolves urinating against trees.
But when oceanographers examined a large group of swirls and whorls drawn off the south-east of Iceland, complete with ships, a giant fish and red sea serpent, they found it corresponded with the Iceland-Faroes Front - where the Gulf Stream meets cold Arctic waters, causing huge swirling eddy currents that could sweep a ship off course.
All too often the ancients are dismissed as ignorant torch carriers in the face of enlightened science. But as my old grad school professor used to point out, mankind forgets at least as much as it learns.
[Link via LRC]