The presidential campaign of 1896 was one of the most exciting in American history. The central issue was the country’s money supply. An economic depression had begun in 1893, and public opinion—and even the Democratic Party—was split between those who favoured the gold standard and those who favoured free silver, a type of currency inflation, to help alleviate the depression. Most Republicans, as well as Democratic supporters of Pres. Grover Cleveland, were in favour of the gold standard. Southern and western Democrats and Populists (also known as the People’s Party)—many of them farmers who were suffering financially—vied for free silver, which ultimately helped bring those two parties together.
This doesn't fully answer but I guess it gives you more info
It was a mixture of various reasons, although for the Spanish and Portuguese it was a question of reaching India for spice trades after the embargo instated on them by the Ottoman Turks.
The Portuguese went around Africa, and the Spanish tried sailing west across the barren ocean, and accidentally discovered America through Columbus.
