This quirky UFO-shaped curiosity is often mistaken for the airport’s control tower.

If all members were present at the table, a sixth of the world's wealth would be under the same roof.

The world's largest fire hydrant is supposedly tornado-proof.

Civil War Fort on an island in the Boston Harbor.

A steampunk wonderland that preserves America's history of industrial innovation.

The fifth-longest natural arch in the world, and the longest outside China.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

The cluster of boulders near Fort Irwin is covered in military insignia.

One of America's most historic homes also holds a startling literary legacy.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

This cemetery served as the only official burial grounds in Cambridge for nearly 200 years.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

This titanic steel chain linking two buildings was installed without permission but instantly beloved.

This grand stone tower was dedicated to a famed American humorist almost by coincidence.

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

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

The Virginia farm where John Wilkes Booth met his grisly end is now largely forgotten.

This Boeing KC-97 tanker is now a restaurant for aviation lovers.

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

A building so large that it has its own weather.

This peaceful Massachusetts graveyard was one of the first "garden-style" cemeteries in America.

The iconic Manhattan corner that was once the site of the Beastie Boys' fake clothing store.

A spooky and decrepit mental health facility is slowly being replaced with newer digs.