Smeatons Tower is the third and most notable Eddystone Lighthouse. It marked a major step forward in the design of lighthouses.
Recommended to the task by the Royal Society, civil engineer John Smeaton modeled the shape of the lighthouse on that of an oak tree. He pioneered the use of "hydraulic lime," a form of concrete that will set under water, and developed a technique of securing the granite blocks together using dovetail joints and marble dowels. Construction started in 1756 and the light was first lit in 1759.
While in use, Smeaton's lighthouse was 59 feet (18 metres) in height, and had a diameter at the base of 26 feet (8 metres) and at the top of 17 feet (5 metres). The foundations and stub of the old tower remain on the Eddystone Rocks, situated close to the new (and more solid) foundations of the current lighthouse - the foundations proved too strong to be dismantled so the Victorians left them where they stood (the irony of this lighthouse is that although the previous two were destroyed, this one proved to be stronger than the rock upon which it was built and could not even be intentionally taken apart).
It remained in use until 1877 when it was discovered that the rocks upon which it stood were becoming eroded—each time a large wave hit the lighthouse it would shake from side to side. Smeaton's lighthouse was largely dismantled and rebuilt on Plymouth Hoe, in the city of Plymouth, as a memorial to Smeaton. It is currently open as a tourist attraction and at 48ft in height provides views across Plymouth Sound and the City of Plymouth.