What were the effects of the Spanish-American War?

The largest effects of this war were that it ended the
Spanish Empire and began the American one.

The Spanish
Empire had been in a long, slow decline for more than two centuries and by 1898 had very
few colonies under their control.  By challenging and defeating the Spanish, the United
States for the first time became a colonial power, taking Guam, the Philippines and
Puerto Rico as US territories.

This ended easy Spanish
access and influence in both the Caribbean and Asia and gave the Americans bases to
project their military power (especially the US Navy) around the globe, securing
resources and trade routes.  The Spanish-American War ended the long era of Spanish
naval power.

It also led to a long guerrilla war fought by
Filipinos against their new colonial rulers, the Americans.