These disused steel furnaces are now haunting ruins that may one day be a national park.

The last street in Pittsburgh that's paved with wood.

An outlet for connecting to memories of lost loved ones and saying goodbyes you never got to say.

One of the tallest buildings in Africa provides a great view of Johannesburg's unique geography.

Mutant vegetables, transgenic mosquitos, and atomic rodents span the walls of this one-of-a-kind museum.

After covering almost 1.5 billion acres, the survey's still not finished.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

This abandoned dream castle and its cemetery look out over the city that once inspired their creation.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

Memorializing an American tragedy of massive proportions.