There's a dyke ( Offa's Dyke) that seperates Wales from England.
(Offa's Dyke (Welsh: Clawdd Offa) is a large linear earthwork that roughly follows the current border between England and Wales. The structure is named after Offa, the Anglo-Saxon king of Mercia from AD 757 until 796, who is traditionally believed to have ordered its construction. Although its precise original purpose is debated, it delineated the border between Anglian Mercia and the Welsh kingdom of Powys.)
Many don't know about this dyke. Also, I've read the the world's highest concentration of O type blood is in Wales.
Most of the DNA in Wales has its origins in the Iberian Ice Age refuge.
There's another dyke (Angela Merkel) that is eliminating the separation of Europe from North Africa.