France–United Kingdom relations May 1994. The same year the American Society of Civil Engineers elected the Channel Tunnel as one of the seven modern Wonders of the World. 11,675,910 passengers in 2008 travelled on flights between the United Kingdom and France. There are lists of twinnings (including those to towns in other countries) at List of twin towns and sister cities in France and at List of twin towns and sister cities in the United Kingdom. France–United Kingdom relations France–United Kingdom relations are the relations between the governments of the French Republic and the United Kingdom of Great Britain and Northern Ireland (UK).
Channel Tunnel techniques from the oil industry were employed. Tunnelling was a major engineering challenge, with the only precedent being the undersea Seikan Tunnel in Japan, which opened in 1988. A serious risk with underwater tunnels is major water inflow due to the pressure from the sea above, under weak ground conditions. The tunnel also had the challenge of time: being privately funded, early financial return was paramount. The objective was to construct two rail tunnels, apart, in length; a service tunnel between the two main ones; pairs of cross-passages linking the rail tunnels to the service one at spacing; piston relief