Medellin is a huge city, but it isn’t that crazy of a city. That said, everyone can use some peace and quiet sometimes. Medellin has you covered. Just go to the botanical gardens. They are right on the metro, but you feel like you are out in the country.
There is a lagoon:

Robert and Lisa by the lagoon
With turtles basking in the sun:

Turtles in the sun
And ducks full of interesting colors:

A colorful duck
And birds that look prehistoric:

A bird
And lizards (that we saw on the ground, in the water, and scampering up the trees) that have to be prehistoric (pretty sure these guys are largely herbivores as we saw them eating the lily pads):
And a fun statue:
And a bamboo garden:

Robert in the bamboo
And beautiful flowers:
And a butterfly house:
When you are done, you can go to the food court on the other side of the metro and eat chicken the Colombian way — with your hands while wearing disposable plastic gloves!