Which war was fought at the end of the nineteenth century?

Spanish American War, is the right answer.

Explanation:

The Spanish–American War was an equipped battle between Spain and the U.S. this war took place in the year 1898. The roots of the war can be observed in the aftermath of the domestic combustion of USS Maine in Cuba, heading the United States to intrude in the War of Independence of Cuba.

the roman empire began to fall