Answer:
In a nutshell, the Crusades helped to end the Feudalism
The Crusades were one role in the vast play we call the decline of feudalism. How did these military movements help? The Christian armies that were going to retake the Holy Land were making the economy work. They had to buy and sell goods, promoting a trade exchange that was crucial to the urban renaissance. Beyond this economic factor, the Crusades were responsible for a cultural exchange that was good for Europe. The contact with other cultures and points of view helped to open the continent to new ideas, turning the feudalism an outdated system.
It was the "Open Door Policy" that was the name of the trading policy that Secretary of State John Hay initiated with China and the European nations that already had a presence there, since the US wanted to benefit from trade with China as well.
An important resource that Spain wanted from the colonies was gold.
