Built high above the winding Yantra river, Veliko Tarnovo's whitewashed structures with red tile roofs appear to be perched one on top of another, almost hanging from the hills, and look as if they could collapse, domino-style, into the valley below.
The city is important in Bulgarian history -- it was the nation's capital from the 12th to the 14th century during its time of medieval greatness, when it was considered second only to Constantinople in its splendor. Today, it's a university town, which leads to a vibrancy among the historic buildings.
Situated in Bulgaria's mountainous interior, Veliko Tarnovo is reached via a bus ride through the country's agricultural breadbasket, with the hills and mountains rising to meet you as you approach. Most river cruises offer it as an included daylong excursion from the Danube port of Rousse, which itself is pretty dull; if this is your first time in Bulgaria, go.