WW1 was the first war to abandon the line styles of "Noble Fighting" found in contemporary Europe. In the old style soldiers walked in line and proceed to shoot each other till the other fled or simply all died. In the horrific new war trenches were dug and six machine gunners could hold off and assault of thousands of contemporary linemen. Doing so led to the horror of trench war which was bloody much more violent and dark.
Answer: Stock Market Crash of 1929 signaled the great depression. This was a quick decline in stock values.
The turning point in Greek history is considered to be the "Peloponnesian War", since it was during this time that Sparta waged war against Athens and significantly diminished the Greek influence in the Mediterranean.
