In more recent years, major transport projects have affected the Domain. The most significant of these was the building of the Cahill Expressway in 1952. As part of this project to build an eastern tributary to the Sydney Harbour Bridge, the small roads to the north and east of the Domain were widened into expressways. After the completion of the project, traffic moving south from the Bridge could pass through a tunnel built into the western part of the Royal Botanic Tunnels, after which it became a sunken road built into the northern edge of The Domain. The road crosses the eastern part of The Domain in a tunnel, exiting through the slope on the east side of The Domain, after which it continues south along the eastern edge of the Domain as the Eastern Distributor. The Cahill Expressway emphatically separated The Domain from the Royal Botanic Gardens, and destroyed the close spatial relationship between the Gardens and The Domain. Between 1958 and the 1960s, the Cahill Expressway resumption and construction work began, dissecting The Domain and Gardens, partly destroying Fig Tree Avenue (first entrance, planted 1847) and loss of 24 palm trees and 12 other trees lost. The Domain and the Botanic Gardens were sewered for the first time since 1792. Then in the 1970s, the rail tunnel for the Eastern Suburbs Line was built under the southern part of the Domain: the railway exits the tunnel on the eastern slopes of The Domain, after which (owing to the large change in ground elevation) it becomes a viaduct. In 1992, the Sydney Harbour Tunnel was built, with its southern section under the northwestern part of The Domain.