Princess Fiona's Tower

Princess Fiona's tower is the tallest tower of the Dragon's Keep where in "Shrek" Fiona was locked in there until Shrek rescues her.

In Shrek 2, Prince Charming arrives to rescue Fiona from this tower but, all he finds is the wolf who tells him that Fiona is already rescued, married, and currently on her honeymoon with Shrek.

Shrek revisits the tower in the alternate reality in Shrek Forever After to try to rescue Fiona again, but all he finds is a torn curtain, several tally charts of how many days Fiona spent in the tower, her tiara and her "favour/token of gratitude" that she gave him in Shrek 1. It is later revealed that Fiona rescued herself from there, which means that Charming either didn't get there in time or was eaten by Dragon.