Surf the Amazon
Talk about extreme sports. The wave in this picture is a natural phenomenon called the Pororoca, an insanely dangerous tidal bore found at the mouth of the Amazon River in Brazil. Around about now (March each year), the sun, moon and earth line up to create the perfect conditions for the biggest bore of its kind (though some say there's a bigger one on the Qiantang River in China). Waves can reach four meters in height, traveling 13km inland from the Atlantic Ocean.
Pororoca, or 'poroc-poroc', means 'great roar' in the local Tupi language, and apparently it sounds like an oncoming train bearing down on you. And it's almost as treacherous as one too. Tidal bores can travel at over 30km an hour, and this one often contains lots of natural debris – like tree trunks, piranhas, snakes and even jaguars.
Still, that doesn't stop thrill-seeking surfers from hitting the brown waves once a year at Sao Domingos do Capim, traveling with them all the way upstream, a journey that can take as long as half an hour (legs and agility permitting). It's been described as the most radical sport there is – as one surfer has said, 'Where else in the world can you go surfing with alligators?' RM