In the late 1400s, Portugal had already set up trade routes along the coast of Africa and all the way to India, and Spain saw the need to compete with the Portuguese. When Columbus proposed to king Fernando and queen Isabel an expedition to explore the Atlantic and find an alternative route to India, the Spanish monarchy accepted since they wanted access to the lands of Asia without having to depend on the mediation of the Venetians and the Ottoman Empire.
As we all know from history, Columbus arrived at the Caribbean in 1492 and reported his discovery to Spain. What would soon follow thereafter was the conquest of the Aztecs, Incas and other indigenous peoples and the subsequent establishment of Spanish viceroyalties in Mexico, Colombia, Peru, Argentina, etc. At the same time, Spain also established another distant colony in the Philippines.
At its height, the Spanish Empire was the most prosperous nation on Earth. Under the Spanish Crown, all kinds of industries flourished from gold and silver mining and sugarcane, tobacco and coffee production to textiles and livestock farming. Latin America wasn't always a collection of underdeveloped third-world countries. It was once infinitely wealthier than most of Europe and the rest of the world.
Here is the Spanish Empire at its greatest extent in 1783:
Unfortunately, Spain went bankrupt multiple times under the reign of Filipe II under the strain of his wars in Europe, and then Spain was ultimately annexed by Napoleon. When this happened, certain criollos (Spaniards born in the New World) saw this historical event as an opportunity to rebel against the Spanish Crown and take regional power for themselves. Conflict ensued between criollo revolutionaries and pro-Spanish peninsulares but, in the end, so-called libertadores, most notably Bolívar, San Martín, O'Higgins and Hidalgo, would declare independence from Spain and establish their own governments which would include the Republic of Mexico and Gran Colombia (before the region further split into the present-day nations of Colombia, Venezuela, Ecuador and Panama).
That is the official history of the Spanish Empire's demise. However, a more conspiratorial viewpoint is that the libertadores such as Bolívar and San Martín were in reality British agents and Freemasons hired by the British Crown to splinter the rival Spanish Empire from within. This conspiratorial viewpoint is reflected in the following Hispanic Unionist song:
¡Traidor, Bolívar, Traidor! (with English subtitles)
In fact, I've watched quite a few videos by Spanish and Latin American historians about the topic of an alleged Anglo-Masonic conspiracy behind the independence movements and ultimately the demise of the Spanish Empire (all in Spanish).
Needless to say, Latin America went to utter shit under the independent governments. The region became little more than a hotbed of political corruption and poverty spread.
Meanwhile, the Yankee Empire established itself as the foremost world superpower. 
National Anthem of Spain: Marcha Real (Alfonso XIII lyrics)