which zoo is the largest one in the world?

It's "Singapore Zoo"

The world's largest zoo, in terms of numbers of different species in captivity, is the Zoologischer Garten Berlin (Berlin zoological garden), itself the first zoo in Germany, opening on 1 August 1844. The 35-ha (86-acre) site currently houses 14,000 animals from 1,500 different species, ranging from panda bears to penguins, and receives on average 2.6 million visitors each year.

The world's largest zoo, in terms of numbers of different species in captivity, is the Zoologischer Garten Berlin (Berlin zoological garden), itself the first zoo in Germany, opening on 1 August 1844. The 35-ha (86-acre) site currently houses 14,000 animals from 1,500 different species, ranging from panda bears to penguins, and receives on average 2.6 million visitors each year.

then what about Singapore zoo Mr. Akram ? because Singapore coming 1st if i am not wrong :)