Plovdiv is the second biggest Bulgarian city, placed in the middle of the country on the banks of the Maritsa River. It can trace its history back for millennia (8000 years) and there are old Roman ruins around the town, most notably a large amphitheatre, which also serves as an outdoors concert venue.
The old part of town has steep cobblestone streets with colorfully painted ancient houses, most of them museums and art galleries. From the old town there is a marvellous view over the entire area. The rest of Plovdiv is dominated by several hills with park areas. Tourists who make the effort to walk up some of the hills will be rewarded by spectacular views across town.
Plovdiv can serve as a base for explorations of the surrounding area where old monasteries and churches abound in the mountains. Also hiking trips are an option.