The International Astronomical Union approved the first names of extraterrestrial mountains (together with many other traditional lunar names) in 1935, although without a generic Latin term, which was restored in 1961. As of May 2015, 262 extraterrestrial mountains and mountain systems have official names: 117 on Venus, 50 on Mars, 48 on the Moon, 23 on Io, 13 on Titan, 9 on Iapetus, 1 on Mercury and 1 on Tethys. They are named differently on different celestial bodies: