The Denver Zoo is tops! Clean, easy to navigate and not ridiculously spread out. They offer an easy-to-read map with admission. I love their primate exhibit and while I am not an animal rights expert, it appears that the habitats are like the real thing appropriate and safe for the animals.
For the money (and they offer many free days for local residents as well as an annual pass) you can't beat the Denver Zoo. We always take out of town company there. It is well-shaded in summertime and the exhibits are educational as well as interesting. Plan to spend the day!
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