What were the 3 main reasons European explorers had to make ocean voyages in the late 1400s and early 1500s?

One reason for exploring was to find an alternative trade route to Asia.  Europeans frequently traded with merchants from China and other Asian countries, but travel to that region with difficult and time-consuming.  Some of the routes were also "controlled by other countries that blocked direct trade between European and Asian nations."  Christopher Columbus was one of the explorers whose goal it was to find a sea route to Asia.

Another reason for exploring and...

One reason for exploring was to find an alternative trade route to Asia.  Europeans frequently traded with merchants from China and other Asian countries, but travel to that region with difficult and time-consuming.  Some of the routes were also "controlled by other countries that blocked direct trade between European and Asian nations."  Christopher Columbus was one of the explorers whose goal it was to find a sea route to Asia.

Another reason for exploring and making the voyage across the ocean was to conquer and claim land.  Once European rulers knew that there was a vast amount of land that was somewhat uninhabited and unclaimed by other nations, they sought to claim it for their own.  Cortés and de Soto were two famous Spanish conquistadors who claimed land for their country.  One reason that they claimed the land was to gain riches from it.

A third reason for exploration was to spread the message of Christianity.  Some explorers believed that their journeys were the will of God.  They believed it to be their duty to convert the native people to Christianity.