The American colonies chose to declare independence from Great Britain for many reasons. They believed the British were treating the colonists unfairly. The British passed many tax laws that impacted the colonists. The colonists had no representatives in Parliament to vote on or discuss these laws.
I would say that Christopher Columbus was influenced by the travels of Marco Polo.
He was greatly inspired by his travels and wanted to become as famous as Polo was as an explorer, and eventually, he did follow in his footsteps. Polo's travels changed the European perception of the Asian world, and as you know, Columbus also wanted to go to Asia, but he ended up in America.
The Great Depression is an effect of the stock market crash