There are hundreds of towers in Kongpo, Minyak and Gyalrong build between 600 and 1800 years ago! These regions were Tibetan cultural borderlands but are apparently related to the Minyak people originally. These towers were build out of stone and mortar in star and rectangular shapes. Some of the towers are more than 60 meters high! Most of the towers are in ruins but still standing. Two are in near perfect condition. The people who live near the towers allegedly do not use them or know their original purpose (although one person in the video says they were used for fighting - in fact the author determines four purposes).
Dr. Darragon's article about the towers in Internationales Staedteforum Graz. April 2007, in English and German.