Creepy old castle

[rebbonk]

A young American tourist goes on a guided tour of a creepy old castle. At the end of the tour, the guide asks her how she enjoyed it. She admits to being a bit worried about seeing a ghost in some of the dark, cob-web filled, rooms and passages.

"Don't worry," says the guide. "I've never seen a ghost all the time I've been here."

"How long is that?" asks the girl.

Spoiler:

"About three hundred years."