How nitroglycerine explodes - in slow motion
The detonation of the sensitive explosive nitroglycerine has been filmed in extreme slow motion for the first time.
Engineer Jem Stansfield visited the Defence Academy of the UK to carry out the dangerous experiment.
A hit with a hammer was enough to set the explosive off, creating a supersonic shockwave and a flash of light almost too fast to film, even with the latest specialist cameras.
Explosions: How We Shook the World is on BBC Four, Wednesday 13 October, 2000 BST and will be available afterwards on iPlayer.