Roald Dahl Plass or the Oval Basin as it was formerly known was the seaward entrance to the West Bute Dock, once the biggest masonry dock in the world. If you look around the amphitheatre style construction you might still see the stone outline of the former dock. The dock was opened on 8 October 1839 and is said by many to be the day that the Cardiff that became the world's greatest coal port was born.
"The second Marquis of Bute was persuaded to finance the £350,000 construction as he already owned most of the land in the area. It was a huge amount even for the Marquis."
Geography Still available as a .pdf is this really handy walking tour of Cardiff Bay prepared by BBC South East Wales: