httpv://www.youtube.com/watch?v=z0_nuvPKIi8&feature=player_embedded#!

At the Solar Furnace Research Facility in Southern France, Jem Stansfield from BBC’s Bang Goes The Theory (the one with Liz Bonnin in it) tests out a super-efficient mirror, capable of focussing sunlight to a 3,500°C point heat source: hot enough to melt rock.

BoingBoing