Season 3
Episodes
1 Berlin Wall Mar 14, 2006 2 Impossible bridges: Denmark to Sweden Apr 18, 2006 3 Impossible Bridges: Greece May 2, 2006 4 Apache Helicopter May 13, 2006 
5 Hoover Dam May 16, 2006 6 Inside NCIS May 30, 2006 7 Impossible Bridges:China Jul 11, 2006 8 Garbage Mountain Aug 1, 2006 9 Ice Hotel Aug 1, 2006 10 Machines of War: Tanks Aug 17, 2006 11 Supertanker Aug 31, 2006 12 Machines of War: Missiles Sep 7, 2006 
13 How it's built: Steel Sep 21, 2006 14 Machines of War: Guns Oct 12, 2006 15 Panama Canal Unlocked Oct 19, 2006 16 Science of Bricks Nov 2, 2006 17 Science of Concrete Nov 14, 2006 18 Megafactories Ferrari Dec 7, 2006 19 Ultimate Structures: Super Pipeline Dec 18, 2006 20 Rockeaters of Iceland Dec 31, 2006
5 Hoover Dam May 16, 2006 6 Inside NCIS May 30, 2006 7 Impossible Bridges:China Jul 11, 2006 8 Garbage Mountain Aug 1, 2006 9 Ice Hotel Aug 1, 2006 10 Machines of War: Tanks Aug 17, 2006 11 Supertanker Aug 31, 2006 12 Machines of War: Missiles Sep 7, 2006 13 How it's built: Steel Sep 21, 2006 14 Machines of War: Guns Oct 12, 2006 15 Panama Canal Unlocked Oct 19, 2006 16 Science of Bricks Nov 2, 2006 17 Science of Concrete Nov 14, 2006 18 Megafactories Ferrari Dec 7, 2006 19 Ultimate Structures: Super Pipeline Dec 18, 2006 20 Rockeaters of Iceland Dec 31, 2006