The Louvre in Paris is one of the largest museums in Europe – and the world.
25,000 to 30,000 people visit the place each day this time of year.
So you'd think they have security under control.
Well, apparently not.
200 staff members walked out for the day there, essentially shutting the museum down.
They were protesting against having to put up with pickpockets who've been targeting staff and tourists at the museum.
Maia de la Baume is a reporter for the New York Times in Paris.
She says pickpockets have long plagued the museum, but their attacks have been increasing lately.