The Waltz was introduced into the United States in the mid-1800's. The standard Waltz tempo at this time was still very fast and quite demanding to the average dancer, and before long, composers were writing music which was much slower. From this music evolved a style of Waltz called the Boston, with slower turns, and more longer, gliding movements. While the Boston eventually faded away, it did stimulate the development of what we now know as Slow Waltz.
Waltz is a smooth progressive dance characterized by long, flowing movements, continuous turns, and rise & fall. It takes a bit more effort to learn at first compare to other dances, but the patience really pays off. At first you have to learn to navigate through the dance floor without bumping into other dancers. After you get past the basics of the movements; the patterns becomes easier to grasp and you will be gliding smoothly through the dance floor in no time.