This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

This odd California folly seems like it was almost designed to accumulate urban legends.

The oldest active mini golf course in the U.S. has an elegant Art Deco style filled with lush tropical plants.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

The sculptor was instructed to add “stallion attributes” to the general's bronze mare.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

This unassuming passageway played a key role in one of the most important events in U.S. history.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

The Corinthian columns that towered over Abraham Lincoln’s inauguration stand proud.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

Around 100 sculptures from artists all over the world decorate the hiking trails surrounding this locale.

Few other hotels can rival the grandeur of the Castle in the Rockies.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

These pretty kitties killed and ate as many as 135 railway workers.

In 2010, Nicolas Cage purchased two plots in this cemetery using one to construct this strange pyramid mausoleum.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

The unbelievably opulent home built for an infamous newspaperman.

At 207 feet, one of the world's longest continuous escalators.