The All-Smelling Tower is a tower in the Kingdom of Springfieldia.
King Quimby told his sorcerers that he wanted an all-seeing eye tower and not an all-smelling tower, because they accidentally made an all-smelling one. The nose at the top of it sniffs and sneezes.
Behind the Laughter
The All-Smelling Tower is a parody of the All-Seeing Eye of Sauron from The Lord of the Rings franchise.