D). Vast empires.
Classical civilizations developed vast empires, whereas early river valley civilizations did not.
Answer:
The Battle of Stalingrad
Explanation:
It is famous for its line "Not one step back!" The Battle of Stalingrad (23 August 1942 - 2 February 1943) was a major battle on the Eastern Front of World War II in which Nazi Germany and its allies fought the Soviet Union for control of the city of Stalingrad in Southern Russia, on the eastern boundary of Europe.
The Spanish conquistadors sailed over the Atlantic to conquer Mexico and Peru in the 16th century.
