Inhabited since: 3000-4000 BC
The earliest evidence of a settlement in the area dates back to 6000 BC. Today, Plovdiv is the second-largest city in Bulgaria. Located in a large plain between two mountain ranges, the city hides traces of its long history. Romans as well as Ottoman Empire once ruled over the city leaving behind numerous architectural marvels including a large mosque in the center of Plovdiv. The Roman Amphitheater discovered in the old town center only in 1970s is a must-see for any visitor and so are charming lanes and cobbled streets with merchants selling art.