Bolero was written by Maurice Ravel as a ballet to accompany physical activity, rather than to listen to. Famous dancer Ida Rubinstein commissioned it in 1928 for a dance recital, although it took on an independent existence to become the most popular work Ravel ever composed. It has been called "hypnotic," "boring," "nerve-wrecking" and "captivating." Undoubtedly it has been all these things to different listeners.
Bolero is defined as a lively Spanish Dance but Ravel's version was in no way a Spanish Bolero. The basic rhythm pattern remains, but the tempo of this work is much slower than the bolero dance. Ravel's Bolero is basically built upon two tunes repeated about eighteen times in the piece.
Imagine this rhythm:
"Dum diddle di dum diddle di dum dum Dum diddle di dum diddle di diddle di diddle di"
Repeated without a break for fifteen minutes. This is the relentless, driving rhythm of the snare drum. The first part of the basic theme is presented by the flute. Then beginning with the bassoon, the wind instruments in turn take up the melody or some variation of it. The tunes are passed around the orchestra, from the oboe to the flute to trumpet to tenor and soprano saxophones. This repetitive tune gradually grows in volume until the full orchestra plays as loud as possible. Most of the piece sticks to one key, C Major. This explodes into a powerful, cumulative and liberating discord in G Major, announcing the finale. It is, in any event, the world's longest musical crescendo. Ravel himself always conducted it with rigorous precision and did not allow the slightest variation in tempo.
Bolero was used in the film 10, with Dudley Moore wooing Bo Derek. Here, it was used to accompany a different sort of physical activity. It was also used in Torvill and Dean's 1980s Ice Dance routines.