Indianapolis Zoo
Indianapolis used to keep various animals in various parks around the city before creating a formal zoo in 1906 near the current Riverside location. WW1 kiboshed the zoo as conservation measures made it difficult to feed them, so they sold off the animals.
Fast forward to WW2, and how times have changed. In the middle of the war, a campaign was started by a local newspaper columnist to create a formal zoo in 1944. It took 20 more years and then finally in 1964 in Washington Park (far from the current location) a zoo was finally opened and formalized. This is the zoo I remember as a kid.
Well, if you've been to Washington Park, it's an ok, but not ideal, location for a zoo, and in 1984 they began moving it to White River state park (the new size of the area really helped).
The Arrival
My daughter and I walked from our hotel in downtown west to the zoo, an easy walk into the park but the entrance is not near the bridge, so we had to take a bit of a roundabout way to get in to the somewhat non-animal area at front.

Tropical plants in the hothouse

There are some butterflies flitting about here also

Trying to prevent extinctions planet wide

Cool 360 immersive views
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Then it was to the first aquatic center, with much marine life on display and some you can even interact with.

Seals

Seals saying Hi!

Various underwater displays of aquatic life

Rays and sharks touch tank, a ray went nuts and absolutely drenched both of us just walking by

Not sure why Macaques are part of water animals, but I'm no zoologist!
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And then onto aquatic center #2, which is specifically only for dolphins who are quite playful and interested in people around the viewing areas.
Then we ventured further into the zoo for a desert biome. Now, there is what we call Indiana Hot in the summer. It's hot, it's really hot, but inside this building? WOW, almost unbearably hot, how the animals in here survive is incredible and quite a nod to the diversity of the planet.

Realistic and live habitat

Turtles walking around

The Sandcat, my daughter almost died of the cute

All kinds of lethal snakes
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Onward to the orangutan center, which, I could not get my daughter interested in going into, so, here is the skyway and some of the outside areas used for exercise and to keep them apart when there are issues.
Now, the plains area, many African animals and the train! (the zoo has had a train since the 60s and as a kid this was my favorite part, and I am sure the site of tantrums afterwards).

Zebras and wildebeests meandering about without predatory pressure

Rare gazelles

The first of 3 elephant enclosures

The 2nd enclosure, larger, with multiple elephants

Warthog, if you saw this in the wild, you're probably looking at a funeral

The cheetahs, my favorite animal in the world

Rwar, the ladies were quite loud that day

The train!!!

Quite a decently lengthened trip over the plains and through the support areas
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And now the birds and ubiquitous zoo carousel!

Inside and up close with the birds

Yes, this close

And even closer

Carousels seem to be the thing zoos need now
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And finally, the forest animals area, where you see things that scare people in Grimms fairy tales, and really cool animals too!

Does a bear hide in a cave?

He was enjoying a cool bath in this heat

Sooo, you're inside with them, and supposedly can pet them, but I just came back from Australia, and I would not suggest it
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There is also a picnic area and some cafes around with hot food on demand.
Tropical plants in the hothouse
There are some butterflies flitting about here also
Trying to prevent extinctions planet wide
Cool 360 immersive views
Seals
Seals saying Hi!
Various underwater displays of aquatic life
Rays and sharks touch tank, a ray went nuts and absolutely drenched both of us just walking by
Not sure why Macaques are part of water animals, but I'm no zoologist!
Dolphins lording above us
Realistic and live habitat
Turtles walking around
The Sandcat, my daughter almost died of the cute
All kinds of lethal snakes
The Skyline, where you can see a bit of the zoo from an eagles view
Orangutan looking bored off his ass
Zebras and wildebeests meandering about without predatory pressure
Rare gazelles
The first of 3 elephant enclosures
The 2nd enclosure, larger, with multiple elephants
Warthog, if you saw this in the wild, you're probably looking at a funeral
The cheetahs, my favorite animal in the world
Rwar, the ladies were quite loud that day
The train!!!
Quite a decently lengthened trip over the plains and through the support areas
Inside and up close with the birds
Yes, this close
And even closer
Carousels seem to be the thing zoos needs now
Does a bear hide in a cave?
He was enjoying a cool bath in this heat
Sooo, you're inside with them, and supposedly can pet them, but I just came back from Australia, and I would not suggest it
Picnic area, partially rented out to a private group
The zoo shop with the zoo things!
Summary
This zoo has a special place for me as it's the first zoo I remember. In my home state, and it's also quite large and super environment appropriate for the animals enclosed.
You can kill an entire day here if you want, and probably will.