A rainbow is an optical phenomenon that can occur under certain meteorological conditions. It is caused by refraction, internal reflection and dispersion of light in water droplets resulting in a continuous spectrum of light appearing in the sky. The rainbow takes the form of a multicoloured circular arc. Although a rainbow spans a continuous spectrum of colours, it is traditionally assigned a discrete sequence, with red, orange, yellow, green, blue, indigo and violet as the most common list. The rainbow inspired the rainbow flag, a symbol of LGBT pride and Pride Month. This portion of a rainbow, appearing to rise from a lakeside forest, was photographed in 2005 in Jasper National Park in Alberta, Canada.Photograph credit: Wing-Chi Poon