Sixteen metres, twice a day.

Every coast has tides — the gentle pull of the moon and sun on the ocean. Most places rise and fall by one or two metres. Fundy amplifies that movement to extremes because of three things acting together:

• Shape — the bay narrows and shallows toward its head, squeezing incoming water higher and higher, like a wave rushing up a beach.
• Depth — the length and depth of the basin match the natural rhythm of the tide (12 hours 25 minutes). The water sloshes back and forth in perfect resonance, like pushing a swing at just the right time.
• Volume — roughly 160 billion tonnes of seawater move in and out each cycle. That's more than the combined flow of every freshwater river on Earth.