Collegium Maius is one of the few remaining medieval university buildings in continental Europe. It is the oldest building of the Jagiellonian University and it has been in use continuously for over 600 years. Formerly, professors used to live and teach here, and afterwards the building was turned into a library. Nowadays, Collegium Maius is the seat of the Jagiellonian University Museum, one of the richest and the most beautiful museums in Poland. You can find here memorabilia of Polish kings, statesmen and great scholars, priceless works of art, scientific instruments and the medieval University insignia. The clock in the courtyard measures time persistently and every odd hour (between 7 a.m. and 5 p.m.) the little green door opens and a procession of historical figures accompanied by music takes place. The courtyard is currently used as a venue for concerts, lectures and many other events. The visit to the Museum begins on the 1st floor, which you reach by walking up the stairs. There, a Gothic gold-plated door, called Porta Aurea (the Golden Gate), leads to the exhibition rooms.