Experts look at engineering blunders that have either caused catastrophes or are disasters waiting to happen. They use cutting-edge technology to examine what went wrong and to figure out if they can be fixed. S4 E1 - Mayhem in Minneapolis S4 E2 - Sinkhole at the Museum S4 E3-Train of Terror S4 E4-Terror in Texas S4 E5 - Calamity Comes to Canada S4 E6 - Nightmare in New Orleans...