When Berlin fell in May 1945, the rest of Hitler's empire soon followed. But remnants of it, built over the course of 12 years, can still be seen to this day. Follow military experts as they use the latest drone technology to revisit some of the key sites across the former Third Reich, from the largest bunker in Germany to the secret location of the original Enigma machine codes. Their mission: to understand how the Nazi war machine operated and to understand what led millions of people to accept and comply to the horror of Hitler's ideology.