Saltstraumen, about 30 km southeast of Bodø, is the strongest tidal current on earth. Four times a day, the changing tide pushes vast volumes of seawater through a narrow 150-metre strait connecting Saltfjorden to Skjerstadfjorden. The whirlpools and standing waves can reach three metres in height and five metres in diameter; the noise at full flood — a deep, continuous roar — is audible from the bridge before you see the water.
Timing matters. At slack water the strait looks like any quiet fjord channel. Check tide tables before making the trip — the Norwegian Tidal Water application online gives precise peak times. The viewing bridge is free and accessible; guided boat trips run through the current if you want to be on the water rather than above it, which is a completely different experience. Saltstraumen is also famous for coalfish and cod fishing — the turbulent water concentrates prey and the fishing is excellent year-round.