“Even the biggest tidal races can be caught when they are small,” says sea kayaker Paul Kuthe of the river-like currents, whirlpools, and rapids that tidal shifts can cause in the ocean. “Most can be ...

Incredible footage from Zhejiang, China, shows small boats racing alongside one of the world's largest tidal bores on the Qiantang River on Monday. Dramatic aerial footage captured the scale of the ...