What were the five main countries that focused on colonization and New World exploration?
England, Portugal, Spain, The Netherlands, and France.
England: English settlers explored and colonized the East Coast of modern-day America and Canada, with some minor exploration of the Caribbean region and even Pacific islands like Hawaii (although this was in the 1700s).
Portugal: This tiny nation kicked off the Age of Exploration with their journeys around Africa. Portugal got a little shafted in the New World though; the only major colony they picked up was Brazil.
Spain: Spain basically explored and settled everywhere south of Mexico. In South America, they conquered the Inca. In Mexico, they conquered the Aztec and Maya. They were the first to see the Pacific Ocean going from east to west, across the Atlantic. They got the biggest chunk of the pie - pretty much all of Mexico and Western South America. Their epic silver mine at Potosi nearly crashed the value of silver, because there was simply so much of it!
The Netherlands: One of the minor players. They're mostly known for their colonization of the East Indies, i.e. Indonesia, but also picked up a few colonies in the Caribbean. They also did some exploring in the New England region and are famous for purchasing Manhattan Island from Native Americans for $24 (though it may have been a little more than that).
France: French explorers were pioneers, exploring the Ohio River Valley and trading furs with the natives. Their colonies at one time included some Caribbean Islands, like Haiti, and the Mississippi River Valley (the latter of which was sold to America in 1803 for $15 million).