Plura River cave diving

The Plura River emerges from a large cave entrance about 30 km to the northeast of the town of Mo i Rana, Norway. Diving at this site is a fantastic experience. The visibility is excellent and the passage is easily big enough to drive an underwater scooter along. The first flooded section of passage (called a siphon) is 450 m long and you reach a maximum depth of 34 m. What makes the scenery so remarkable is the rock of the cave, which has been folded and worked by geological processes as though it were pastry, leaving swirls and patterns in the walls. The erosion by water has accentuated these patterns—different layers in the rock are more or less soluble and the less soluble layers often standout like hundreds of teeth—it feels just like swimming into the mouth of a shark!
Beyond the first siphon are some magnificent chambers with high ceilings that soar up above you, and where even the sound of a drop of water echoes all around. The flooded cave then continues down to depths of over 100 m—these passages are only accessible to extremely well-trained experts.
Access to the cave is limited to qualified cave divers only, but occasionally, training courses are run at the cave where you can take a cave diving certificate. It's also sometimes possible to take a cavern diving course. In this course you are limited to the first 50m of the cave where the daylight still shines in, but even at this distance you can really appreciate the beauty of the cave.