The Bay of Fundy is a bay between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the US state of Maine. It has an extremely high tidal range. The tidal range in the Bay of Fundy is about 16 m. Because of tidal resonance in the funnel-shaped bay, the tides that flow through the channel are very powerful. In one 12-hour tidal cycle, about 100 billion tonnes of water flows in and out of the bay, which is twice as much as the combined total flow of all the rivers of the world over the same period. They are as powerful as 8000 train engines or 25 million horse power.