I've been reading about the Great Depression and it's effect on Germany in the gap between both the wars.
One thing which I don't understand is that how did Nazi Germany became so powerful under the regime of Hitler though Germany was economically weak during this period?
From where did Hitler bring in all the economic resources to manufacture Panzer tanks/Fighters for Luftwaffe etc.
In short, how did Nazi Germany became powerful so quickly and nearly took over the world in such short time?
The answer is relatively simple, they just focused much more on it then most other people. From the very beginning of the regime rearmament was the major focus of the regime. The amount of government budget dedicated to the armed forced rose extremely fast with few exception all the way up to 1939.
The restricted other imports in order to focus on things need for war material. The had special institution to improve branches of the military and infrastructure needed for military. Sometimes the just took over companies. There are many more things that are not worth going into detail over.
The were one of the most taxed countries in the world by 1938 and even then inflation was already starting.
However even with all that, because of the Depression and the general weakness of the german economy, the other nations could outproduce the germans. Once they started to focus more budget on the armed forced, they started rapidly catching up. France was not weaker in numbers of men or equipment. Britain was far ahead in terms of Navy and even produced more airplanes the early periods of the war.
nearly took over the world in such short time
The never nearly took over the world. They made a very good offensive against France and kicked them out. The english were getting ahead in airplanes and were pretty effective at hunting german U-Boats. Even in the middle east and Egypt the Brits did ok in the early part of the war. Then the nazis attacked the USSR and never managed to defeat it.
The attack on South Russia (ending in Stalingrad) was the last major offensive that the were able to mount. After that it was just a slugfest, slowly pushing them back, on all fronts. They were outproduced by every one of the other combatant.
You can not take over the world if you are not able to defeat Britain and the US, neither were in real danger of losing the war. Defeating the USSR was a long shot, they hopped the USSR would simply collapse.
tl:dr; Major focus on military, but not enough to come even close to world conquest.
Source:
As many analyses have shown, the amount of material such as tanks and fighters for France and the USSR was not inferior to that of of the Germans, in fact France started out with (on paper) a superior, more mechanized force than Germany in the battle of France. But the numbers were not enough for total superiority (like the allies of 44-45) and French strategic blunders are what lost them the battle.