The most accurate timepiece in the world.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

A historic ruin just 20 feet away from a busy highway onramp.

A painfully obvious spy house sits right across the street from the Russian Embassy.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

A wondrous old library overlooking the nation's capital.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

The oldest house in Chicago certainly doesn't look the part and there are some who say it doesn't deserve its title either.

Despite its name, this fast food museum is actually a replica of the ninth McDonald's store.

This historic store hides a museum exhibiting a shoe-sizing x-ray machine and a pair of kicks that once belonged to the world's tallest man.

A science teacher's dream.

Cemetery featuring rare glass-fronted columbarium.

Chicago's North Park Village was once the largest municipal sanatorium in the country.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

One of two side-by-side totem pole parks dedicated to educating visitors on Tlingit history and culture.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Abraham Lincoln's likeness rests at the top of this giant totem pole.

I-95's Tijuana-style celebration of kitsch at the Carolina border.

"Not too many people can say they've had a nuclear bomb dropped on them, not too many would want to." — Walter Gregg.

The site of one of history's most indelible and horrific tragedies.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.