I’m almost sure it was a round tower, however, I remember there was a spiral stairs like you would see in a round tower. You went up to the top and could feed the giraffes because you were at their height. This also featured in a magazine in the 1990’s. I’m not sure if the magazine was a TV guide and there was a documentary. The pictures were taken from outside and there was a young girl in the picture with blonde hair. This is not the place in Nairobi, Kenya.
I don’t know that’s the main issue. I’ve spent hours googling and nothing. The only thing I know was it was a tower and had stone spindle stairs. And a room at the top with a window you could feed the giraffes.
There is an article entitled 'People involvement innovations at the Honolulu Zoo' in International Zoo Yearbook 15 (1975). A photo in this edition shows a structure with two towers, each containing a spiral staircase, linked by a short elevated walkway with guardrails, beside the giraffe enclosure. This should be available on-line, but behind the Wiley-Interscience paywall.
