Autumn in the Southern Hemisphere is when swell trains wake from their summer slumber and start to roll out of the Southern Ocean. According to Surfline guru Nick Carroll, this body of water is “the world’s greatest swell machine”. Building up steam and whipped by strong winds these southern swells don’t stop until they hit land, or in the case of Teahupo’o in Tahiti, a shallow reef shelf that rears rapidly from a deep seafloor, creating some of the world’s wildest waves in the process.