A good zoo has an accurate environment that does not stress out the animals and educates people about the environment and ways to help. They also help repopulate wild populations of animals.
For example the San Diego Zoo is one of the best zoos in the world the animals there live without getting stressed by tiny enclosures and boring concrete walls. Animals here live to their full life expectancy
A bad zoo
A bad zoo doesn't take the animals needs over profit. The animals quality of life is stressful and short and often ends painfully. These types of zoos don't see their animals as living creatures but profit generators. They often spend very little on the animals food or welfare
An example of a bad zoo would be the Mumbai zoo it doesn't help its animals and doesn't care when they die instead taxidermising them then putting them on display for the public. Here an animals life expectancy is very low. By doing this they encourage poaching.
The pentagon will be our enclosures put together to make the the terra loop. There will be a railway traveling through the encolsures the carriage will be about 1.5m of the ground letting animals pass underneath. Each pod or carriage will be a glass dome that hangs from a elavated rail so that you feel like your sourounded by nature.