A time when the economy collapsed worldwide and millions were unemployed.

The great depression

Explanation:

The Great Depression was the worst economic downturn in the history of the industrialized world, lasting from 1929 to 1939. By 1933, when the Great Depression reached its lowest point, some 15 million Americans were unemployed and nearly half the country's banks had failed.

Explanation:

to contain the wave of communism

an era of negotiation.

is that an answer to your question?