In the setting of a typical Amsterdam canal house in the Wallen district, there is an unusual museum. The museum, which was formerly a secret Catholic church, was founded in 1661 when the authorities of the Netherlands introduced a strict reform regarding the faith of Catholics. This unique museum-church with a no less unique name - "The Church of Our Lord in the Attic" occupies the top floor of the house, which is reached by an old wooden staircase. Decorated in the style of Dutch classicism, the temple of the church with 150 seats continues to function at the present time. The church hosts Catholic services, holy masses on weekends and holidays, accompanied by organ music and a choir, and people often come here to get married. In addition to the church, museum guests can see the rest of the house, which also has its own secrets.