A strange alien shrine on a mountain peak, a bridge built in the Alaskan wilderness, and an American castle with a dangerous secret are mysterious deserted engineering projects, and new discoveries reveal how they were built.
Stories:
1) Buzludzha Monument, Kazanlak, Bulgaria;
2) Miles Glacier Bridge, Alaska, USA;
3) Bannerman's Castle, New York, USA;
4) Georg Thiele, Narvik, Norway
