The sitar is the most iconic instrument of North Indian classical music. It is a plucked string instrument with a long, hollow neck and a gourd resonator. What gives the sitar its signature 'twanging' and 'shimmering' sound is its use of sympathetic strings. While a sitar may have 18 to 21 strings, only 6 or 7 are actually played by the musician. The remaining strings sit beneath the frets and are never touched; instead, they vibrate automatically in 'sympathy' when the corresponding notes are played on the main strings. The frets are curved and movable, allowing the player to pull the strings sideways—a technique called 'meend'—to achieve the vocal-like glides essential to Indian Ragas. Ravi Shankar is credited with introducing the sitar to the West, famously teaching George Harrison of The Beatles how to play.