England's largest castle was founded in the 11th century and is known as the 'Key to England' due to its defensive importance throughout history. It stands in 100 acres of ground with history dating back to the Iron Age. Visitors can explore the anti-aircraft room and telecommunications station where Winston Churchill oversaw operations during WWII. In recent times, English Heritage have spent £2.45 million recreating the castle's interior. There is free on-site parking, local bus routes and access from Dover Priory, one mile away.