The vast prayer hall of the mosque houses the remarkable collections of the Archaeological Museum, which include: stelae, epitaphs, low-relief carvings and an exceptional set of Thracian votive stones (2C-3C). Mural paintings, originally in the Bulgarian churches of Krapec and Melnik, are displayed on the mezzanine. Adjacent rooms contain valuable works by goldsmiths from the North-Western part of the country. However, the prize exhibit is the Thracian treasure of Valcitran (12C-15C BC), which consists of tableware in solid gold.