Unfortunately, the tower was built on weak, unstable topsoil which began to shift shortly after they constructed the third level. Instead of trying to shore up the lean, the builders continued to add more floors to the tower over a one hundred year time span. In this case, the foundation was faulty which has impacted the tower structure.
Ephesians 2:20-22 says we are "...build on the foundation of the apostles and prophets, with Christ Jesus himself as the chief cornerstone. In him the whole building is joined together and rises to become a holy temple in the Lord. And in him you too are being built together to become a dwelling in which God lives by his Spirit." The Message translation puts it this way, "God is building a home. He's using us all--irrespective of how we got here--in what he is building."
But you and I can't do what God created us to do if we have a foundation that isn't rooted in God's Word and continually growing in Him. The Tower of Pisa wasn't built to lean; it was built to stand!
The tower is actually a bell tower, built behind a cathedral. Bell towers are built to proclaim news to the townspeople. Get in the Word so you can get the Word out!