The Maritsa river flows past this country's second largest city at Plovdiv and empties into the Aegean Sea after acting as the border between Greece and Turkey.
One city in this country is the site of a Friendship Bridge connecting that city with this country's neighbor's city of Giurgiu. That city is sometimes known as Little Vienna, and is called Ruse. Components of its only nuclear power plant at Kozloduy were required to be put out of commission upon this country's entry into the European Union in 2007. Another city in this country lies to the north of the (*) Vitosha massif and lies near the largest river entirely in this country, the Iskar River. That city contains the large Amphitheatre of Serdica. The Maritsa river flows past this country's second largest city at Plovdiv and empties into the Aegean Sea after acting as the border between Greece and Turkey. For 10 points, name this Balkan country on the Black Sea with capital at Sofia.
One city in this country is the site of a Friendship Bridge connecting that city with this country's neighbor's city of Giurgiu.
Bulgaria [accept Republic of Bulgaria]