Making cairns--balancing rocks on each other--is an art form, a hobby, and a craze with a growing community around the world. Eight-stone cairn of river rocks stands up with a little help, held together by pre-drilled holes, metal pegs and finished with glue, so it is stable and built to last. Place indoors or out. No two are identical. About 13" high. Excess glue can be easily removed.