The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

The U.S. Supreme Court's secret Cold War relocation facility in the mountains of North Carolina.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

The Lincoln Memorial has inspired many, even though a word on the inscription appears to be spelled incorrectly.

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

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

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

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

The site of William McKinley's tragic assassination is only marked by an underwhelming boulder.

This restored house is like a time capsule of the president's unconventional inauguration.

A massive Montreal stadium that has seen nothing but trouble since its inception.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

The vaulted ceiling is home to a scurry of “squirrelgoyles.”

Small ship votives hang from the vaulted ceiling of this port-side church with a Latin inscription on the wall.

A historic Montreal market that was the city's agricultural hub for over century.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

One of Canada's oldest museums, the beautiful Redpath has been serving up Natural History and Ethnography since 1882.

Go inside the house that inspired L. M. Montgomery to create one of literature's most beloved heroines.

The Magic House provides a beautiful and creative environment for curious youngsters to get their knowledge on.

What was meant to be a temporary exhibit is now a permanent fixture at the St. Louis Zoo filled with beautiful birds.

A historic house in St. Louis was plagued by a series of suicides committed by family members involved in a successful brewery.