After some discussion, it turns out that the top of the shiny, shiny TransAmerica Pyramid is made up of bunch of Gothic-looking paned windows that protect the 6000-watt halogen disco ball within. You see, sometimes, when the sun’s at just the right angle, total internal reflection kicks in and all that’s visible is a ball of light.
You can see the effect of the metal frames holding the glass here in a nice 30-second nighttime exposure from Flickr’s exxonvaldez, who really ought to consider changing his handle to exxonmed or searivermediterranean or just plain mediterranean.
Click to expand:
Top it off with a lighting rod and you are good to go.
Look for it the next time you’re at a Anonymous vs. Church of Scientology protest / rally / whatever at Washington and Montgomery