Wikipedia EN Nera (Donau)
The Nera (Romanian and Serbian Latin; Serbian Cyrillic: Нера, Hungarian: Néra) is a 124-kilometre-long (77-mile) river running through Romania and Serbia. It is a left tributary of the Danube, which it joins near Banatska Palanka. Its length is 143 km (89 mi) and its basin size is 1,380 km2 (530 sq mi) (Black Sea drainage basin). The Nera is not navigable.
Source: Wikipedia https://en.wikipedia.org/wiki/Nera_(Danube)