On the very long list of things to film while on a visit to the Bronx Zoo, a large rock is likely near the bottom of the list for most people. But here's a man who knows his rocks:
The Rocking Stone was, according to reports of the time, well known in the Bronx before the zoological park opened in 1899, and was even listed in guidebooks to New York City. It is a forty-ton, ice-age glacial boulder composed of pink granite, and 70 lbs of pressure, applied to just the right spot, will cause it to rock about an inch. I've tried many times, but as of yet have been unable to find that "right spot."
The World of Darkness, briefly referred to in the video, was opened on June 12, 1969. I went to see the exhibit that summer - it was state-of-the-art, at the time. They lit the cages with red fluorescent light by day, and turned on regular white lights at night. This caused naturally nocturnal animals to be active during the day (they couldn't perceive the red light) and to sleep at night, when the exhibit was closed. It was closed this year because of budget cuts resulting from the economic downturn.
Update: Okay, now I know why I was never able to find that "right spot" on the Rocking Stone. Apparently the stone was moved from it's original position in 1959 and positioned so it could no longer be rocked. More on that here:
The Rocking Stone and New York City Zoos