A marching band is a group of musicians who play music that has been arranged to perform while marching. Instrumentation typically includes wind and percussion instruments but omits violins and other stringed instruments. The size and composition of marching bands vary greatly, ranging from fewer than twenty musicians to more than 500. In addition to the traditional military marches, special arrangements of other types of music are also often played, including of symphonic music, movie music and popular music. Most marching bands typically wear uniforms while performing, often military-style. Although the music has been arranged to be performed while marching outdoors, it is not uncommon for such bands to perform while seated outdoors or indoors.