Humans have been fascinated by waves for a long time. When the difference in water depth right off a coast is big enough, small waves can grow into huge walls of water - just what surfers are looking for.
Without them, the sound of the sea wouldn't be the same - waves provide the most calming swoosh-swoosh known to man. And there's nothing more beautiful than standing on a beach and watching the waves come in. For surfers, though, listening and watching is not enough. They ride the watery giants, which can rise up as tall as a house. In a storm, nine-meter waves (nearly 30 feet) are not unusual.
The tallest wave ever surfed crashed on the shores of Nazare in Portugal, according to Smithsonian Magazine. The lucky guy on top of the monster, which was almost 24 meters tall, was Garrett McNamara.
Because of an underwater canyon almost 5,000 meters deep that extends right up onto the coast of Nazare, there's a huge difference in water-depth in a very small space. That's why the waves there get so tall. Faced with these mountains of water, surfers might be best off doing what German band Juli suggest in their song "Perfekte Welle," or perfect wave: "This is the perfect wave, this is the perfect day. Just let yourself be carried by it, it's best not to think about it."