Reversing Falls is a rare anomaly of nature. This is where the Saint John River rushes through a narrow gorge before emptying into the Bay of Fundy and then the Atlantic Ocean. The bay is subject to an extreme range of tides of up to 28 feet. During high tide (every 12 hours and 10 minutes), the river runs backwards in swirling whirlpools and rapids. The powerful action is mesmerizing. The gorge was formed about 15,000 years ago at the end of the last glacial period. Geologists suspect three waterfalls once existed here. The cascades slowly eroded into the current view about 3,000 years ago.