The baltimore zoo or the aquarium???...which one is worth the time and money?

Both are really nice, but if I had to choose I would go to the aquarium.

Aquarium, hands down. the Zoo is falling apart and they are unable to fix any of it as the entire place has been designated an Historical building so they can't fix stuff. you have a very long walk(or wait for the tram) to actually GET to the exhibits.

The aquarium is definitely nicer.