The lands that they visited were known as the Spanish main
. From these lands they stole treasures from the Aztecs, in a land now known as Mexico. They loaded their ships and sailed back to Spain in their galleons. However they were often attacked on their way back by Pirates and privateers.
Queen Elizabeth's favourite pirate was Sir Francis Drake who was both an explorer and a privateer and he made it a habit to rob Spanish ships on just such voyages, particularly when the two countries were at war in the 1570s and 1580s. As a reward for his efforts he was knighted in 1581 by the queen.
There were three well known Spanish galleons loaded with treasure from the Spanish main. They were attacked in 1523 by Jean Fleury. He captured two of them and one escaped. One of their features was that they floated high in the water making them easier to load and unload. At the top of their mast was the crow's nest. Here the look out kept an eye on the ship's progress and from here he could spot land more quickly than from the main deck.
In the Caribbean there were many ships with pirates on board looking to rob the Spanish of their treasure. In particular, the pirates who lived on the island of Hispaniola were called buccaneers. There name was derived from the fire on which they cooked their meat, called a boucan. The Buccaneers began attacking Spanish vessels in the 1630's
On of their most well known members was Henry Morgan. He raided Spanish ports and towns in the 1660's and became very rich as a result. He was appointed Lieutenant Governor of Jamaica by the then King of England.