The 2005 archaeological excavations took place in two areas: 1. Inside the Roman-Byzantine Sucidava citadel, in an area named 2003 Surface, where 15 boxes (6 x 6 m) were opened. In C5-C6 and C8 boxes, we found several stone bases, which belong to some constructions slightly elevated, from the 6th century AD. Inside C9 box a stone wall with higher dimensions was identified, a wall that seems to have some connection with the building with hypocaust, from the surrounding area. 2. Inside the citadel, close to the west gate, inside the C1/2003 box, a stone construction with rectangular shape (4.40 x 3.55 m) was discovered. We can remark the special measures taken by the builders in order to carry out a hydro insulation of the construction as efficiently as possible. The explanation is provided by its position, very close to the bank of the Danube River. We suppose that we deal with a tower, supporting the end of a foot bridge that crossed the defense trench of the fortress. It used to make the connection between the foot bridge and the bridge inaugurated by Constantine the Great in 328 AD