Dover Castle built
1179 CE.
Shown on the map at 51.128°, 1.323°.
Dover Castle is a medieval castle in Dover, Kent, England and is Grade I listed. It was founded in the 11th century and has been described as the "Key to England" because of its defensive significance throughout history. Some sources say it is the largest castle in England, a title also claimed by Windsor Castle.
Text from the Wikipedia article Dover Castle, licensed CC BY-SA 4.0.