Dover Castle towers high above the port town of Dover in Kent,
and has guarded this gateway to the realm for nine centuries.
William the Conqueror built an earthwork and timber-stockaded castle here
immediately after his victory at the Battle of Hastings in 1066.
From then on Dover Castle was permanently garrisoned until 1958.
King Henry II began building the present castle in the 1180s and, over the next 800 years,
its buildings and defences were adapted to meet the changing demands of weapons and warfare.
Many centuries before Henry II built his great stone fortress,
the castle grounds may well have been the site of an Iron Age hill fort.
After the Romans invaded in AD43, they built a lighthouse here to guide ships into the harbour.
The Anglo-Saxon church next to the lighthouse was probably once part of a Saxon fortified settlement.
At the centre of Dover Castle is its imposing Great Tower, which Henry II also built.
At just over 25 metres high, 30 metres square, and with walls up to 6.5 metres thick, it has three floors of rooms, with the state apartments for the king at the top.
Henry used this magnificent palace to impress distinguished visitors from abroad.
These included noble pilgrims travelling to the new shrine of Thomas Becket in Canterbury Cathedral,
who was slaughtered by Henry’s knights 10 years before work on the Great Tower began.
Today, the Great Tower is presented as if Henry and his court were in residence.
Many of the reproduction furnishings are based on surviving examples dating from the 12th century.
Some pieces though, such as the thrones and beds, had to be based on manuscript illustrations.
The brightly coloured armoire in the king's bedchamber is a particularly fine example of the replica furniture created for the tower.
From the north-west view of Dover’s barbican
the name for the towers either side of the drawbridge
you can see the castle's outer defences.
During the first half of the 13th century,
King John and Henry III completed the rings of defensive walls surrounding the Great Tower.
These were put to the test during two unsuccessful sieges in 1216 to 1217 and 1265.
Deep below the castle grounds are a series of eerie, winding medieval tunnels,
which were dug during and after the siege of 1216 to protect the most vulnerable side of the castle.
These were then dwarfed by a much larger network of tunnels that were dug in the 18th century,
when England faced the threat of invasion from Napoleonic France.
These tunnels were brought back into service during the Second World War
when they housed the command centre that controlled naval operations in the Channel.
In the castle's tunnels in May 1940
Vice Admiral Bertram Ramsay oversaw the dramatic rescue of British troops from Dunkirk during Operation Dynamo.
Over the next few years the tunnels were extended to serve as a hospital for injured troops,
and as a large headquarters responsible for guarding the Straits of Dover and preparing for the 1944 invasion of Europe.
Today, visitors to the castle can take a tour of its atmospheric tunnels,
explore its Great Tower and walk among its ancient landmarks.
Together, they chart the long and storied history of this imposing coastal fortress.