Airports of London cannot be expanded due to the docks on either side. It is also the only airport serving London which does not operate at night. A light rail service from London City Airport DLR station, which adjoins the terminal building of London City Airport, links it to the financial district of the City of London at Bank and Monument stations, which offer interchanges with London Underground. Located in the London Borough of Hillingdon, Heathrow is by far the largest of London's airports and considered the main gateway into the United Kingdom for non-European visitors. Heathrow has four terminals and two parallel
Timeline of the London Underground of the network. Station names shown are current names; many stations have previously had different names. Timeline of the London Underground The transport system now known as the London Underground began in 1863 with the Metropolitan Railway, the world's first underground railway. Over the next forty years, the early sub-surface lines reached out from the urban centre of the capital into the surrounding rural margins, leading to the development of new commuter suburbs. At the turn of the nineteenth century, new technology—including electric locomotives and improvements to the tunnelling shield—enabled new companies to construct a series of "tube" lines deeper