Before revision: 2008 28 Earthquake Glasshouse Academy of Sciences, California 2008 Season 5 (2009–2010) # Country Title Subject Original airdate Other Airdate Credits 01 Grand Canyon Skywalk Grand Canyon Skywalk 2009-02-28 (NGC UK) 2009-04-02 01 Extreme Helicopter S-64 Skycrane 2009-06-16 02 Skyscraper (Ultimate Skyscraper) Bank of America Tower at One Bryant Park, NYC 2009-10-01 03 UK Super Train / Britain's New Railway High Speed 1 2010-01-08 04 ?
After revision: 2008 28 The Impossible Build Academy of Sciences, California 2008 Season 5 (2009–2010) # Country Title Subject Original airdate Other Airdate Credits 01 Grand Canyon Skywalk Grand Canyon Skywalk 2009-02-28 (NGC UK) 2009-04-02 01 Extreme Helicopter S-64 Skycrane 2009-06-16 02 Skyscraper (Ultimate Skyscraper) Bank of America Tower at One Bryant Park, NYC 2009-10-01 03 UK Super Train / Britain's New Railway High Speed 1 2010-01-08 04 ?