This thread by @The_UltimateBea is called "The Best Zoological City". Different ZooChatters suggested what city they think is the best for zoo nerds. That got me thinking, if there was poll, which city would be voted the highest. So here it is. Each city suggested in that thread has an option on here. *I didn't include Toronto because A. I didn't have room. B. Look at the responses in the original thread. Feel free to vote for Toronto in the thread.
Singapore, they have the Zoo, Night Safari, River Safari, Jurong, the SEA aquarium, and a few smaller places. The next 2 are San Diego and Berlin. I’m not sure why Toronto is mentioned, there’s one pretty good but not great zoo, and a couple of minor collections.
Tokyo is hard to beat...provided we are including the entire Kanto plain. Dallas-Fort Worth (if we accept Fossil Rim as being local to that conglomeration) is also a fair entry.
I vote for Tokyo. Tokyo isn't that hard to beat though. Berlin have 2 great zoo and best collection. Their collection is massive and contains a ton of different things. Singapore is also a great entry, with five zoo attractions there. My vote goes to Tokyo though. It just have so much zoo in the Tokyo Metropolitan area. Ueno zoo is one of the oldest, but contains a variety of species. Inokashira, although small, is not bad at all. Tama is certainly one of the better in Japan/Asia, together with Zoorasia in Yokohama. Just see the definition of "city" or "metropolitan area". Not to mention all of those aquariums inside Tokyo ,some of those that have sunfish and baikal seals.