Just west of downtown, the Reversing Rapids (formerly known as the Reversing Falls (locals went with the more accurate name) is located within an impressive rocky gorge, a natural phenomenon which has been turned into a tourism site. The rapids here reverse because of huge local tides battling against the St. John River’s flow; rapids, small waterfalls, and big, slurping whirlpools flow one way up through the gorge during the incoming tide, then reverse during the opposite tide. It’s dramatic, but it is in a busy part of the city next to highways and across from a paper mill with smokestacks, which will spoil it for some. There are several ways to observe the falls. You can scramble down wooden steps to a park at river’s edge, or climb atop a rooftop viewing platform, both for free. You can cross the river to Fallsview Park (go left on Douglas Ave., then left again on Fallsview Ave.) and get a water-level view. The adventurous can take a Zip Line Tour with Saint John Adventures (www.saintjohnadventures.ca; tel. 877/634-9477 or 506/634-9477), which offers an amazing view of the falls from six towers (five zip lines). Allow about 90 minutes and about C$70 for adults; students and seniors get a discount. Prices vary per season. Participants must weigh between 70 and 270 pounds.