Smoo Cave, Durness 2007
The name Smoo is thought to be derived from the Norse word "smjugg" meaning hole creek or cleft. This impressive sea cave has been carved into Durness limestone by successive episodes of high sea level over the past several hundred years. The huge entrance, the largest entrance of any sea cave in the British Isles is more than 15 meters high and leads into the first chamber which is more than 60 meters long and 40 meters wide. The second chamber, containing the waterfall, is about 21 meters by 9 meters and can be viewed from a specially constructed platform, the third chamber is accessible only by a small boat.
The Smoo burn Allt Smoo drops nearly 25 meters into the second chamber down a vertical shaft, the Falis Smoo or chimney Smoo as the as the sink hole in the roof is called. The burn cascades into a deep pool with a depth of around eight meters. After heavy rain, the Allt Smoo is changed into a raging torrent that crashes into the underground lochan with a gigantic roar. The "blow hole" and waterfall can be observed from an observation point above the cave.