The Jubilee Line Extension (JLE) is the extension of the London Underground's Jubilee line from Green Park to Stratford through south and east London. An eastward extension of the line was first proposed in the 1970s. As part of the development of London Docklands, the line was extended to serve Canary Wharf and other areas of south and east London. Construction began in 1993, and it opened in stages from May to December 1999, at a cost of £3.5 billion.