Cardiff is a port city on the South Wales coast, where the Taf River joins the Severn Estuary. It was proclaimed capital of Wales in 1955. On the re-energized Cardiff Bay is the Wales Millennium Center, which hosts national operas, orchestras, plays and dance performances, as well as Mermaid’s stores. Quay. The Senedd, a state-of-the-art building designed by architect Richard Rogers, is occupied by the National Assembly of Wales.