A theremin is an electronic musical instrument that is played by the movement of two hands without any physical contact, in contrast with all other instruments. Pitch is controlled by the position of one hand near a vertical antenna and volume is controlled with the other hand by its position relative to a horizontal antenna. The resulting sound is most often described as eerie or spooky. Invented in 1920 by Russian physicist Lev Termen for use in performing classical music, the theremin has been used in a variety of music genres of both art music and popular music.