EARTH'S MOST SPECTACULAR PLACES

How do you decide what places to preserve? What makes some spots on Earth more worthy of protection than others? It's a decision most countries struggle with. One big help is that the United Nations Educational, Scientific, and Cultural Organization (UNESCO) has designated 878 places worldwide as "World Heritage Sites." These are locales with outstanding natural or cultural value for the world. The organization works with more than 200 countries to ensure the protection of these sites. The list now has 679 cultural, 174 natural and 25 mixed cultural/natural sites to be preserved.

Here are 10 of Discovery Earth's favorites from the World Heritage Sites list.

Giant's Causeway, Northern Ireland

Over 40,000 massive basalt columns rise out of the sea, the result of volcanic activity on the green isle some 50-60 million years ago.

These strange, stunning columns have spurred myths and research - from legends of giants using them to stride over the sea into Scotland to 300 years of serious geological studies and research.

Credit: iStockphoto