This man’s work is absolutely beautiful. Here’s what I found on artist, William Pye’s site:
The sirens Charybdis and Scylla resided in the Sicilian Sea. Homer tells us that because Charybdis had stolen the oxen of Hercules, Zeus struck her with a thunderbolt and changed her into a whirlpool whose vortex swallowed up ships. In Charybdis the circular movement of water inside a transparent acrylic cylinder forms an air-core vortex in the centre. Steps wrap around the cylinder and allow spectators to view the vortex from above. The cylinder was manufactured in Grand Junction, Colorado.
Charybdis is William Pye’s largest vortex water sculpture to date, and he has used for only the second time the clear acrylic polymer he employed in Clearwater Cube. This material has enabled Pye to extend his sculptural language and to explore more ways in which to challenge the wayward element of water. A high level of water filtration is essential for maintaining transparency and thereby expressing the drama of the vortex.
Pictures and text from http://www.williampye.com/sculpture-3.php?id=34
Check this one out too, by a different artist (unknown) in Kanazawa.
The Water Clock