I am an expert art historian, I guarantee a detailed and fascinating explanation, with a well structured tour, which will include radio guides if you exceed 10 people in the group, so you can hear perfectly every explanation. Usually groups will be small and the service will be friendly. You will understand the evolution of the building and the incredible fusion of styles that makes it unique in the world.
For a full refund, cancel at least 24 hours before the scheduled departure time.