The three features are, Rhine River, Dounbe River, and the Carpathians Mts.
They were the rivers Rhine and Danube and the limes Germanicus, a series of fortifications between the two rivers.
The Danube River formed the northern boundary of the Byzantine Empire for much of its existence. It served as a natural barrier against invasions from various tribes and peoples in Central and Eastern Europe. The river was crucial for trade and military movements, facilitating connections between the empire and its northern territories.
Hadrian's Wall in Britain the Danube River in Continental Europe
Hadrian's Wall, the Rhine River, and the Danube River
The Syrian Desert.
The three features are, Rhine River, Dounbe River, and the Carpathians Mts. They were the rivers Rhine and Danube and the limes Germanicus, a series of fortifications between the two rivers.
The natural borders in the northern parts of the Roman empire in what can be called "central Europe" were the Rhine and Danube rivers. Incursions by Germanic Tribes for example were an ongoing problem for Rome. In the ending years of the empire, these river boundaries were crossed en mass by barbarians.
Hadrians wall
mediterranean sea
The Tigris River was not the northern boundary of Alexander the Great's empire. Instead, his empire extended further north into regions that include parts of present-day Turkey and the Caucasus. The Tigris River, along with the Euphrates, was significant in the region of Mesopotamia, which Alexander conquered, but it did not define the northern limits of his vast empire. The northern extent of Alexander's campaigns reached into areas like Bactria and Sogdiana, well beyond the Tigris.
The western boundary of the Roman Empire was the Atlantic Sea. The eastern boundary was Persia (modern day Iran and central and southern Iraq).
From Libya to Central Asia.
The two rivers that form the northern border of the Roman Empire are the Rhine and the Danube. The Rhine flows primarily through modern-day Germany and the Netherlands, while the Danube traverses several countries in Central and Eastern Europe, including Germany, Austria, and Romania. Both rivers served as significant natural boundaries for the empire, facilitating trade and military defense.