How does dressage work?

Dressage is what many people would consider the Ballet of the horse world. What appears beautiful and effortless to the audience is in fact an achievement in art and athleticism requiring years of development and dedication for both horse and rider. Dressage is performed in a 20 x 60 meter arena with a set of letters that designate where movements are to be executed; the letters also assist the rider in judging specific distances, such as the size of a circle. In addition, lower level tests may also be adjusted and performed in what is referred to as the short arena, which is 20 x 40 meters