ood base for viewing.
POROROCA TIDAL BORE, AMAZON RIVER, BRAZIL
At the mouth of the Amazon, the Atlantic's tide occasionally – when the moon is right – gets the better of the outpouring river. The result: the longest tidal wave on earth. In the predawn light you'll hear the monkeys screeching and a distant dull roar before you see the wave – all 4 metres of it charging upstream, taking all manner of shoreside debris, and some very intrepid surfers, along with it. The surfing record to date is a 12.5km ride lasting 37 minutes. You'll be able to enjoy the spectacle at the annual National Pororoca Surfing Championships in São Domingos do Capim in March.
The pororoca occurs twice a day, three days a month; waves are biggest in February and March.
RACETRACK, CALIFORNIA, USA
Who wouldn't expect a few oddities in a place like California's aptly named Death Valley? Prime among them is the mystery of the 'racing' stones in the valley's remote north. These large, flat stones, some of which weigh as much as 180kg, have 'raced' across the earth, leaving grooves in the dry, cracked lake bed behind them. Nobody has actually ever seen any of the rocks move, and science's best guess is they've been blown across at times when the lake bed is slippery from rain or frost.
You can camp in Death Valley, but with furnace-like temperatures you might prefer an air-conditioned lodge (www.nps.gov/deva).
This is an extract from Lonely Planet's 1000 Ultimate Sights © Lonely Planet 2011. RRP: $34.99. lonelyplanet.com