The Cairo Metro opened on September 27, 1987, at which time it was the first subway to open on the African continent. As of 2015, it has three lines and 61 stations along nearly 50 miles of track, with extensions to the existing network and a fourth line being planned. About 4 million passengers use the system daily. Line 2 has the distinction of having the first tunnel of any sort to be constructed under the Nile River. A single ride costs 1 Egyptian Pound, or roughly 0.13 US dollars, making it the cheapest subway ride in the entire world.