A look at ten of the world's most beautiful caves.

Renewable energy power plants are usually upgraded before they fall into disrepair. Yet sometimes relics of a renewable past are left scattered across the landscape.

Fascinating man-made islands and floating communities including a former fort fit for a Bond villain and a picturesque Pacific garbage dump.

These animals, whether they were invited, invading, or simply curious, have found their way, unexpectedly, into urban areas.

Inspirational globes for Earth Day inspire a sense of unity and invokes the urgency for everyone to get on board with the green movement.

Cars are great, but have you ever wanted to get rid of yours? There are cities out there where it is possible to get by and get around without getting into a car.

From a Mayan treehouse playground of the rich to the home of descendants of Bounty mutineers, here are 10 mysterious and unusual islands.

The world currently has 121 gigawatts of installed wind power. But not all wind farms were created equally.

These 12 visionary films create dismal futures caused by present-day problems like global warming, wildlife extinctions and resource depletion.

Going off-the-grid often means traveling to somewhere remote, but it doesn't have to. Cutting-edge constructions mean that unplugged, self-sufficient sites can be found both in the city and in the countryside

Bamboo is a versatile material that is only now reaching its full potential, being used in all kinds of creative and unusual ways. Some of these, though, might be a bit much.

Greenery isn't just for roofs. These 15 beautiful buildings feature walls decorated with trailing vines, moss, sedum and other plant life.

Incredible things can be made of dirt, as shown by these 15 examples of earthen architecture including adobe pueblos, hobbit holes and modern marvels.

This article describes the hottest, wettest, driest, highest, lowest, tallest, coldest and other most extreme locations and places on earth.

The world's deepest and most deadly dive sites include old nuclear missile silos, blue holes, artificial dive pools and caverns over 300 feet deep.