About 50 million years or so ago, Costa Rica was a series of underwater volcanoes. Over thousands and thousands of years, layers built up until eventually they surfaced and continued to grow, just as the Hawaiian Islands do today. The Cocos Plate shoving its way underneath the Caribbean Plate also helped things along, pushing Central America out of the sea floor. Eventually, a recent 3 million years ago, Costa Rica emerged from the sea creating a continuous bridge between North and South America
