Check out this UK video of a row house explosion. Taken by the Engine cam, it's frightening and amazing at the same time.
Right before the explosion, a group of firefighters just rescued a bunch of people from their houses after a report of a kitchen fire. While they were still cleaning up, the house exploded with an incredible force. Several bursts of flame, flying glass, the works. Two of the houses were partly destroyed and four had significant damage from the blast.
The cause of this explosion was a cooper thief who cut a nearby overhead line. This produced an electrical disturbance that reacted with the gas lines in the houses. Add some electrical sparks to highly combustible gas and you get a big boom. Thankfully, no one was seriously hurt in the blast. [Hat Tip to Jonathan Seal, Youtube via The Examiner]