Museums and private collections in Bulgaria preserve thousands of items with inestimable value. Among them are the applications discovered in the Varna Chalcolitic Necropolis at the beginning of 1970-s - the oldest processed gold in the world, the treasures of the Thracian rulers from the 2-nd and 1-st millenium BC, hundreds of artifacts from the Greek city-states on the coasts of Black and Aegean seas, finds from the 20 large cities of the Roman empire dispersed over present day Bulgarian lands, from their heirs in the Byzantine empire. Among them are also the treasures of mediaeval Bulgaria and the wonderfully worked production of Bulgarian craftsmen created under the Ottoman Empire. Seeing all these will give you very good impression why Balkan Peninsula is often called "crossroads of civilizations" - fine example is the history of one specific item from the National History Museum - a Chinese porcelain bowl brought by Venetian tradesmen in Bulgarian lands, where a Greek orthodox priest has binded it and turned it into a vessel for baptism.