Ahoj ! I don't know if anyone can tell me what this is a picture of ? Yes, embarassingly it's mine, and was taken from the walls of the Castle. I was in such a rush to try and cover everything I forgot to find out.. If I didn't know better I'd say it was a catacomb - my Czech friend (who also doesn't know) says that the Castle does have these.. Thanks in advance !
This is garden of "Wallenstein Palace" (in Czech - Valdštejnský palác). It is seat of Senate of Czech Republic. The strange thing on the wall is Grotta - artificial garden cave. Better picture is here.