The Drobeta was a fort built by Emperor Trajan in the province of Roman Dacia, in the present city Drobeta-Turnu Severin. It was built to protect the northern side of Trajan's Bridge across the Danube which was built quickly in preparation for Trajan's Second Dacian War in 103-105 AD. It was therefore in a key strategic location from where the imperial road north into Dacia started.
Around it developed the Roman city of Drobeta.
The fort has been extensively excavated and is visible today.
Wikipedia https://en.wikipedia.org/wiki/Drobeta_(castra)
Coordinates 44°37'29.511" N 22°40'5.079" E
