The Channel Tunnel (French: le tunnel sous la Manche), also known as Chunnel or Eurotunnel is a 50.450 km (31.35 mi) long rail tunnel beneath the English Channel at the Strait of Dover, connecting Folkestone, Kent in England (51°5′49.5″N1°9′21″E) to Coquelles near Calais in northern France (50°55′22″N1°46′50.16″E) The "tunnel" consists of three separate tunnels; two 7.6 m (25 ft) diameter single track, single direction rail tunnels which are 30 m (98 ft) apart and one 4.8 m (16 ft) diameter service tunnel between them. It was a megaproject with several false starts, but it was finally completed in 1994. It is the second-longest rail tunnel in the world, with the Seikan Tunnel in Japan being longer, but the undersea section of the Channel Tunnel, at 37.9 km (23.55 mi), is the longest undersea tunnel in the world.