The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

This too-low North Carolina railroad trestle is still a notorious big rig executioner.

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.

This mountaintop lake bubbles and steams in a perpetual boil, thanks to its direct link to the Earth's interior.

Rumored to be the famed pirate's lookout tower, this historic stone structure is now just watching for tourists.