The ruined Norman castle, which was begun by William the Conqueror in 1070, is one of the most ancient in Britain.
The castle became a ruin in the 17th century after it was constructed as one of the three royal castles in Kent in the reign of Henry I (1100-1135). It became a prison in the 14th century as it became overshadowed by the bigger fortifications in Dover.
Today little remains of the interior, but you can climb part way up the towers and relax or explore the gardens.
Opening times: From morning until dusk
The great fortress of Dover Castle has long been known as the ‘key of England’ due to its crucial role in the defence of the realm.
Built in the 12th century, Dover Castle is one of the largest castles in England and provides a spectacular site above the famous white cliffs. It has hosted royal visits from Henry VIII, Elizabeth I and Charles I’s queen, Henrietta Maria.
From the 1740s onwards the medieval banks and ditches were reshaped and the castle was adapted for artillery warfare, before more additions were made to the castle’s defences in the 18th century when England faced invasion from Napoleonic France.
To house the huge numbers of troops needed to man them, a network of tunnels was dug in from the cliff face for use as barracks.
Visit www.english-heritage.org.uk to find out the latest prices and opening times.
Eynsford Castle is an example of an early Normal enclosure castle.
The castle has been largely abandoned since the 14th century after it became the subject of a disputed inheritance and was subjected to vandalism. It was then used as hunting kennels and stables in the 18th century.
Today, parts of the castle wall survive to their full height alongside the remains of the hall where the inhabitants once lived.
Opening times: 10am to 4pm October to April, 10am to 6pm, from April to October.