HOW is the Leaning Tower of Pisa Inside?

Standing on the square underneath the Leaning Tower, you cannot help appreciating its majesty. It stands tall and it leans upon you.
There is something magic about it.
The entire monument is made out of solid rock. You look at it from the bottom up and you cannot really grasp how much work it must have been necessary to put all that together.
On top of that, each stone is different. There are literally thousands of little details and features sculpted in the white marble!
You are enchanted by its beauty.
Then a question arises...
How does it look on the inside?