Every year in May, during the European Funds Open Days, the Opera at the Castle opens its doors to visitors. Guides tell stories about the interiors and during a unique walk they present the theatre spaces renovated and reconstructed thanks to European funds: the reconstructed O. Gallery located in the north wing, the modern foyer, the underground hiding the castle foundations and the heart of the opera: the main auditorium with one of the most modern stages in Europe. While wandering around the castle one may admire posters and costumes from the current shows of the Opera at the Castle. The sightseeing is enriched with titbits from the life of the theatre, presentations of different stages of the reconstruction and prize competitions.