I've found 5 cultural tours to Bulgaria

The Danube from Romania to Germany with 1 Night in Bucharest and 2 Nights in Transylvania (Expression)

Follow the graceful waterways from the Danube Delta through the Balkans, Hungary, and Austria with stunning views along your Danube River cruise.

From Romania to the North Sea with 1 Night in Bucharest (Passion)

Glide past quaint towns, beautiful views, and historic buildings along the Danube, Main, and Rhine Rivers.

The Danube from Romania to Germany with 1 Night in Bucharest (Expression)

Germany River Cruise: Explore Europe from the Black Sea to Germany on this Avalon river cruise. Cruise from Bucharest to Vilshofen. Request a quote!

From Romania to the North Sea (Passion)

From Romania to the North Sea with 1 Night in Bucharest and 2 Nights in Transylvania (Passion)

Your Danube River cruise takes you to the capitals of three countries: Belgrade, Serbia; Budapest, Hungary; and Vienna.