What causes tides and why are some tides extreme?

The answer

Tides are caused primarily by the gravitational pull of the Moon and, to a lesser extent, the Sun on Earth's oceans. When the Sun and Moon align during new and full moons, their combined gravity produces especially strong spring tides. The Bay of Fundy in Canada holds the record for the world's highest tides, with a range of up to 16 meters, caused by the bay's funnel shape and the natural resonance period of its water matching the tidal cycle. Tidal forces also gradually slow Earth's rotation by about 2.3 milliseconds per century.