A view inside the Roman Lighthouse at Dover Castle in Dover, England.  The lighthouse (Roman Pharos) is the oldest surviving lighthouse in the country – and one of the oldest in the world, dating from around 46-50 AD(during the reign of the Emperor Claudius) and just after the invasion of Britain in 43AD.

The original octagonal structure was 80 feet tall and consisted of six to eight storeys of which only four remain today. It was apparently built as a replica to the design of Emperor Caligula’s lighthouse at Boulogne-sur-Mer near Calais on the northern coast of France, built in 40 AD. (There was a second Roman lighthouse at Breden-stone on the Western Heights but nothing much of that remains).  A beacon of fire would have burned on the top of the lighthouse enabling Roman sailing vessels crossing the channel between Gaul and Brittania to navigate their way safely into the harbour.

The Roman Lighthouse has been repaired and reconstructed over the centuries with the uppermost masonry being mostly medieval.  The Lighthouse now sits in the grounds of Dover Castle which was founded in the 11th century, directly alongside the late Anglo-Saxon church of St Mary-in-Castro, which is itself constructed from Roman building materials, built in 1000AD. The working church was partly rebuilt in the medieval era, and was restored by the Victorians after many years of neglect.  

In the 13-14th century the lighthouse was in use as a church bell-tower and it was at this time the medieval stonework was added to strengthen the top section, making it look more like a fortified ‘church tower’ with battlements.  Today the Lighthouse is only a four-storey building at 64 feet high, with the top floor section being the medieval restoration.  After nearly 2,000 years the original Roman stonework on the seaward-side is inevitably weather-worn and crumbly, though the top medieval section is still in a resonable state of repair.  Local black flint from the Dover Cliffs was used in the lighthouse construction.

More info here: https://www.historyhit.com/locations/the-roman-lighthouse/