I have been to many zoos in my life time but so far Portland Oregon's zoo beats them all. I have been three times and each time I go, I am a little more amazed than I was the last time.
The zoo has so many things for children to see and do. It keeps them busy all day while they are there. I am constantly being nagged about going from my nephew because he likes to see all of the animals.
Portland Zoo has been around since the 1800's and was created by a seaman by the name of Richard Knight. He used to collect animals and keep them in the back of his pharmacy. In 1887, he presented his collection to City Park and thats how the zoo was created. In 1894, the zoo grew to about 300 specimen, mostly from North America and has gotten bigger through out the centries.
As I have said before, the zoo has many things for kids. For instance you will find a Red Ape Reserve, an Aviary with wild birds, an African Rainforest, giraffes, elephants, rhinos, monkeys, turtles, and caimans. You will also find bears, lions, and tigers.
The zoo has a very informative history shp as well as a gift shop with lots of zoo merchandise that you can purchase. There is also a train that takes you around the park and gives you all of the zoo's history.
If you live in Portland or are just visiting, I would suggest that you come vist.