Port Jackson, commonly known as Sydney Harbour, is a natural harbour on the east coast of Australia, around which Sydney was built. It consists of the waters of Sydney Harbour, Middle Harbour, North Harbour and the Lane Cove and Parramatta Rivers. The harbour is an inlet of the Tasman Sea. It is the location of significant landmarks such as the Sydney Opera House and Sydney Harbour Bridge. The location of the first European settlement and colony on the Australian mainland, Port Jackson has continued to play a key role in the history and development of Sydney.