The concerts are held in the just as glorious (and not open so often) Clam-Gallas Palace (Husova 20, Prague 1). The two biggies of Carnevale are the balls, also both held at Clam-Gallas Palace. The first is on opening day, February 25. Called Bellarie, it´s billed as an extravaganza night in masks in which you can enter a world of fantasy, music and joy. Costumes and masks are required. To send you off into Lent on a note of excess, attend the Crystal Ball on March 5 – a great Baroque night of masks.