A limestone chimney 55 metres tall standing on the fjord floor at 70m and reaching to within 15m of the surface, built over…A limestone chimney 55 metres tall standing on the fjord floor at 70m and reaching to within 15m of the surface, built over roughly 11,000 years by hot spring water pouring out of the seabed. You can put your hand in the outflow, 70-degree fresh water venting into a two-degree fjord, and the tower is thick with anemones and wolffish. Hydrothermal chimneys are normally a deep-ocean phenomenon found at thousands of metres. Strýtan is the only one on earth within reach of a recreational diver, which is why it has been a protected natural monument since 2001 and why the local diver who found it, Erlendur Bogason, ended up running the dive centre on the pier. Anchorage: Hjalteyri, an old herring factory pier in Eyjafjörður, with Akureyri at the head of the fjord. Hazards: Two-degree water and a top at 15m with the base at 70m. Drysuit certification required, and the site is protected so nothing is touched. Más