14. Iceland: Few countries rival Iceland’s unspoiled natural beauty, and for good reason: its people go to great lengths to keep their waters some of the cleanest in the world. And its capital city of Reykjavik is perhaps the most energy efficient of them all. About 85 percent of the total energy supply in Iceland is derived from locally produced renewable energy sources, including geothermal energy and hydropower. Creative Commons

Earth Day 2014 is a time to reflect on the great things Mother Nature has done for us – and how we can return the favor.

Over the past few decades, governments and world leaders have become increasingly concerned with the effects of global climate change. The knowledge that we as humans have a hand in the health of our planet is reflected in policies aimed at reducing greenhouse gas emissions, conscious living choices and sustainable initiatives at all levels of society.

While we haven’t always gotten it right, countries all over the world are making great strides to protect the planet.

Every year, researchers from Yale University and Columbia University release a report that documents the sustainable practices of some 178 countries. Called the Environmental Performance Index, the report looks at 20 factors – including things like health effects, air quality, water and sanitation, agriculture, climate and energy – that indicate how “green” a nation is.

Here’s a look at the 14 greenest countries in the world, according to how they ranked on the EPI.