Five amazing tidal bores (VIDEO)

Known as the ‘Pororoca phenomenon’, the size and speed of this Amazon tidal bore has caused it to travel more than 400 miles (645km) upstream. With waves reaching heights of 4 meters, the surge attracts surfers seeking a lengthy, wild ride.

The longest river in the United Kingdom, the Severn is another popular location for surfers thanks to its unusual tidal bore. Enthusiasts who monitor the spectacular event say they expect waves of up to 10 meters high next month.

The island of Sumatra is home to one of the greatest tidal surges in the world, named Bono. With its narrow channel the Kampar River provides the perfect funnel conditions for raging rapids to overcome the flow downstream. Earlier this year, daredevil James Cotton rode into the record books for riding the river tide for 17.2 kilometers without falling.

The rare water surge that travels through the Hooghly River near Kolkata is quick, very quick. So much so, that the event has been christened ‘the Baan’, after Germany’s high-speed autobahn motorway.

An annual event occurring during China’s Mid-Autumn festival, the Silver Dragon has caused rollers of nearly 9 meters to sweep up the Qiantang River, often smashing spectators off their feet.