Fort Sensible is a historical building located in Olde Springfield Towne.
According to the tour guide, the name of the fort was given after a captain was killed by the enemy:
Tour Guide: The enemy surrounded the fort, and said that if the captain was sent out, the rest would be spared.
Bart: What did they do?
Tour Guide: They sent him out!
Bart: Was he killed?
Tour Guide: And how! That's why they call it 'Fort Sensible'.