1,700-year-old Roman watchtower ruins discovered in Switzerland

A drone shot of the area to the north of the watchtower. There is a wide river running from the top left to the bottom right of the image. On the bank closest to us are lots of trees (without their leaves). On the far side of the bank there is a small town.

The remains of a Roman watchtower dating to the fourth century A.D. have been discovered by the Rhine River in northern Switzerland. 

The watchtower had a square base measuring 23 feet by 23 feet (7 by 7 meters) and 3-feet-thick (1 m) walls, researchers said in a translated statement. It's not clear how tall it would have been. Not much of the tower itself still remains, but archaeologists found bricks, stones, mortar, roof tiles and a foundation ditch near the Swiss town of Schlatt.