So I started watching video's on youtube to kill some time when unexpectedly I stumbled across an interesting factoid (video here see # 4).

Apparently the Nazi research scientists charged with developing and perfecting new military technology drew up plans for a solar powered death ray that could make the ocean boil or destroy an entire city (allegedly). Fortunately the means and timetable to build this was very impractical.

Also see: Damn Interesting -- The Third Reich's Diabolic Orbiting Superweapon.