A somewhat romantic/poetic name given to the city of Swansea in South Wales
The name refers to Swansea's historical links to the copperworking industry. In fact Swansea town (as it then was) was the largest site of copper production in the UK, and one of the key centres of world copper production for most of the late 18th and most of the 19th centuries. Copper ore was imported mainly from Chile, processed to make copper and used largely for making copper-bottomed ships for the Royal Navy.
During its industrial heyday, Swansea was one of the key centres of the world copper industry, earning the nickname 'Copperopolis'