Serpent's Wall
Serpent's Wall (Ukrainian: Змієві вали, Zmiyevi valy) is an ancient system of earthen fortifications (valla) that stretch across all of Ukraine, from the town of Zmiiv in the east to Podolia in the west. They seem to be similar in purpose and character to Trajan's Wall situated immediately to the west. The remaining ancient walls have a total length of 1,000 km.
The ancient walls were built between the 2nd century BC and 7th century AD, according to carbon dating. There are three theories as to what peoples built the walls: either the Sarmatians against the Scythians, or the Goths of Oium against the Huns, or the Early East Slavs against the nomads of the southern steppes. In Slavic culture, the warlike nomads are often associated with the winged dragon, hence the name.