Up in northern Norway, the maelstroms—oceanic whirlpools—are legendary. Every six hours, and most powerfully when the moon is full, the world’s strongest tidal current roars through the 150-meter-wide (490-foot) strait of Saltstraumen. Ten-meter-wide (33-foot) whirlpools spin at 20 knots like giant washing machines. The phenomenon attracts rich fish life and white-tailed sea eagles to the channel that’s 10 kilometers (six miles) from Bodø. Zodiacs get you close and under the soaring, 768-meter-long (2,520-foot) Saltstraumen Bridge that links the islands of Knaplundøya and Straumøya.