A dolos (plural dolosse) is a concrete block in a complex geometric shape weighing up to 20 tons, used in great numbers to protect harbour walls from the erosive force of ocean waves. They were designed and developed by two local Harbour Engineers in East London, a port city in South Africa, in 1963 and are now found in their millions around the world.

Each dolosse is numbered so that they can be monitored and surveyed to check on movement and any remedial work that might be required to ensure adequate protection to the pier wall or shoreline. It’s amazing to think that the ocean contains that much pure power that it can actually move any of these interlocked 20-ton concrete giants but I’m told that it frequently does!

552 of these incredible 20-ton giants were used to line the new Durban harbour entrance piers along with 7,792 smaller concrete Antifer Blocks. You certainly need the agility of a mountain goat to climb out on them to take photographs!