The only Bahá'í house of worship in North America and one of only a handful worldwide.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

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.

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

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

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

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

A celebrity from the late Cretaceous period.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The most decorated dog of World War I is preserved in the Smithsonian.

The walls of the iconic dome are hollow and have a secret stairway.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

There’s a hidden military meme engraved on the World War II Memorial.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

These 20-foot jaw bones honor a time when the leviathan bones were a sign that whalers survived the hunt.

These planks were originally installed to hold the dead.

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

A world-class observatory in the California desert.

Stripes of flowers bloom each spring in a 50 acre rainbow of color.

A couple turned their front yard into an artistic masterpiece.

One of the largest trees of its kind in California.

North America's largest accredited model railroad museum.

The world's largest outdoor organ is played weekly by one of just two civic organists in the U.S.