It has just over 345,000 (greater metro area 675,000) and is located in the central south, two hours from capital Sofia. And in the more than 30 years since Bulgaria started evolving from a particularly hardline, isolationist Communist country, Europe's oldest continuously inhabited city has reinvented itself for the 21st century, the allures of its picturesque old town and ancient Roman amphitheater these days balanced by vibrant nightlife, cultural ferment, and a parade of exciting festivals and events throughout the year.
Built, like Rome, on seven hills, astride the Maritsa River through the Thracian Plain, the origins of Пловдив stretch back to the first Neolithic settlements of the 6th millennium BCE, and in the millennia since has undergone numerous incarnations. Once known by the Greek name Philippopolis (after Alexander the Great's dad Philip of Macedon, who conqueres the area in 342), it was first part of the kingdom of Thrace and then absorbed by empires including the Roman, the Byzantine, the Ottoman, and the Bulgarian (681–1018 and 1185–1396), before Bulgaria finally became a principality in 1878 - leading to a further tumultuous evolution culminating in its current status as a capitalist parliamentary democracy and member of the European Union and NATO. All of that has bequeathed a tremendous amount of history, it goes without saying, and visitors reap the benefit. And all that history and culture also clinched Plovdiv's selection as one of 2019's two European Capitals of Culture.
Read more about this fascinating city in this post I wrote some time ago, Plovdiv, Bulgaria's Second City, a 2019 European Capital of Culture.