urban thermal warfare
This is the best thing I've read all day; BLDGBLOG on the plastic-melting parabolic reflector that is the Vdara Hotel, aka the Las Vegas death ray:
The surface of the building acts like a parabolic reflector, concentrating solar heat into a specific target area. It's the future of urban thermal warfare, perhaps: hotels armed against other hotels in a robust defense posture defined by pure heat.
Not unimaginable.