"Offa on the Dyke"

Offa's Dyke
Creative Commons Attribution Share AlikeOffa's Dyke - Credit: Chris Heaton
 Offa's Dyke is a huge, 8th century linear earthwork that runs along part of the border between England and Wales. It is attributed to King Offa of Mercia, and originally marked the division between the Anglian kingdom of Mercia and the Welsh kingdom of Powys.