A common feature of the economic development of European countries at the beginning of the 20th century.

Many countries have developed economically due to:
1) Improvement of railways
2) The emergence of aircraft
3) European countries continued to trade with each other
4) the USA was able to rise to a high level, thanks to the First World War
5) Science developed, thanks to which new technologies appeared that sold well on the world market
6) Small countries-colonies under the onslaught got poorer and poorer, resources were taken out of their countries just like that.
In general, large countries continued to develop
Small-poorer
The USA received huge benefits, and the countries of Europe after the war took a long time to correct
But the United States soon took a huge hit in the economy because of Black Friday.