Complex sentence: The vestibule also exhibits a tower that looks from the outside like a low extension of the main tower over the shrine and is hence called by art historian Gerard Foekema as the "nose" of the main tower.
Split into simpler sentences: The vestibule also exhibits a tower which from the outside looks like a low protrusion of the main tower over the shrine. Art historian Gerard Foekema calls it the "nose" of the main tower.