How did the 1930s worldwide depression come about?

The starting point is October 24, 1929, when the strongest stock crash occurred. Unprecedented collapse of stock prices in the aftermath was called "Black Thursday", later on 28 and 29 of the same month, the case took quite a sad turn. This is how "Black Monday and Tuesday" appeared.  

The reasons for this event have not been determined so far, but scientists from all over the world collect a list of individual factors, which ultimately should become a holistic picture. One such factor is the lack of money. At that time, the banks could not print cash in such a volume as now. The lack of funds led to deflation.  

In 1930, people began to massively seize the funds available from banks. A lot of banking organizations have been broke. Six months later, a second wave of bank panic occurred. By 1932, the US GDP fell by 31 percent. It was the culmination of the crisis. The population growth decreased, 23.6 percent of the people crossed the unemployment line, it seemed that nothing could save the economy.

make no change because everything else is correct