Widespread clean-ups of Sydney Harbour have successfully transformed it from an industrial wasteland to a pleasing plunge spot, with several spots in the Harbour safe for swimming, all year round. Marrinawi Cove is one of the first. An idyllic swimming nook tucked away at Barangaroo, it is expected to be followed by many more. Plus, thanks to a big funding boost by the NSW government to rewild the Harbour, a rare seahorse was found living beneath the Opera House. How's that for good news?