The harbour of Donil Vadin, Bulgaria according to a CIA report dated 16 December 1954

An item dealing with the harbours along the river Danube reported that the harbour of Donil Vadin, Bulgaria was just small and used for shipping bread grains from the surrounding area to elsewhere.

Source
The report was published on www.archive.org, document number CIA-RDP80-00926A007500480005-4