"The Earth tide is a little-known daily event, similar to the oceans' more familiar tides. But the sun and moon's gravity doesn’t just pull on water, it deforms the Earth itself, causing the ground beneath us to bulge toward the pulling heavenly body." [more inside]
The Wave Motors of California. "Still embedded somewhere in the shores of California, buried by more than a century of sand, are lost hydroelectric machines." Further reading.
Before, during and after. DigitalGlobe's QuickBird satellite imaged the coast of Sri Lanka at precisely the time the tidal wave hit the beaches. It was pure coincidence.
Mention Whirlpools, and people tend to assume you're talking about a Jacuzzi. But not all whirlpools man-made. When powerful tidal currents are forced between a narrow fjord, and then come up against another current traveling in a different direction, the result is a large water vortex. Being tidal means they are predicable. Some of the more famous whirlpools are the Corryvreckian(Scotland), "Old Sow" (Canada), Moskstraumen and Saltstraumen (Norway), and the Naruto (Japan). Notice how they each claim to be the largest of them all. ...Just one more thing to ponder the next time you pull the chain