"The Cascades" is a piano rag composed by Scott Joplin especially for the 1904 St. Louis World's Fair. The title "The Cascades" refers to a particular feature built for the Fair, a waterfall which cascaded down in multiple tiers and which was floodlit at night. The cover of one of the sheet music editions published in 1904 shows a picture of the attraction with boats on the lake in front of the cascades. The rag's tempo indication is "Tempo di Marcia" or march-time. The piano plays cascades in the B-section which starts in bar 22 and the C-section which follows features octave cascades for the left-hand, which makes this one of Joplin's more difficult rags.
You can download the sheet music, midi and mp3 versions of The Cascades using the links on the left hand menu.