Elevated freight railway turned wildly successful urban park.

Look closely and you’ll notice that the color changes a third of the way up the tower.

A former major munitions plant that has been converted into a sprawling art space.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

This small museum gives visitors a chance to soak up the history of the "sponge capital of the world."

Manatees congregate around a power plant's discharge canal where the water is especially warm.

A luxuriant botanical garden below sea level.

Visitors flock to see this church tower's unintended feature: It happens to resemble a giant chicken from multiple points of view.

Florida might be at its most surreal in this museum devoted to the famed Spanish artist.

The smallest post office in the United States is no bigger than a broom closet.

A monument celebrating the idea of reaching inaccessible places.

The "Gateway to the Arctic" connects Barrow's indigenous population with the sea and its traditional industry: whaling.

The king of U.S. high points towers over every other peak on the continent.

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

Quite simply the largest tree in the world (by volume).

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

Millions of years of oxidation make a drive down this winding Death Valley road surprisingly colorful.

The rocks in this arid basin leave trails of movement behind them.

This crumbling Death Valley mining complex was known for its use of giant, 20-mule team wagons.

This giant temperature attraction created some giant electric bills.

A volcanic tunnel illuminated by natural skylights offers a shaded respite from the desert sun.