Hi there,
The best known underground dwelling is the Cave of the Mounds which is found in the south-central part of the state and it is relatively easy to reach from both Milwaukee and Madison.
In Wisconsin caves, you can expect to see some dazzling stalactites and stalagmites and bats and it is an experience you will not forget soon.
When exploring the
caves, I would also suggest to go with a guide if you are not familiar with the area. It's also a good idea to bring some supplies such as a helmet, flashlights, water, knee pads and gloves.
Hope this helps
Vacationbuddy