Rabaul has a large, nearly enclosed harbour, Simpson Harbour. These harbours were both of a similar size to Dover harbour. There are international cruise ship docks in South Harbour, Katajanokka, West Harbour, and Hernesaari. Nelson has beaches and a sheltered harbour. Wadden Sea is an important habitat for both harbour and grey seals. Sydney has traditionally been the main port, with facilities in a large, sheltered, natural harbour. The city has an industrial harbour, Copenhagen Port. Aden encloses the eastern side of a vast, natural harbour that comprises the modern port. It is a developing area with narrow old lanes leading to a small fishing harbour. Today it hosts yachting events around its large harbour. Bull sharks have attacked swimmers around the Sydney Harbour inlets. It is housed in a modern building with a panoramic view over the harbour. It is from Nafplion, which was its historic harbour. The monument faces towards the Mumbai Harbour. There are areas of quicksand close to the harbour.