I mean, water carved this cathedral out of nothing. DR DAVE THAYER: Yep. MICHIO KAKU: And how long has this erosion been taking place? DR DAVE THAYER: Well at least 5.5 million years is what they say.

Download/print a transcript of the video. Liz Bonnin introduces the water cycle - part of Hydrology ... Amazon River as it travels downstream. The erosion of the Grand Canyon.