This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

The idyllic colonial home of the artist behind the famous portraits of George Washington and Thomas Jefferson.

The final resting place of New England's last "vampire."

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Sacred Indian temple that’s all monkey business.

The world's second-largest sundial, made entirely out of stone.

The 953 windows undoubtedly make this the world's most beautiful screened porch.

Soldiers carved these regimental badges into the chalk hills in remembrance of those who died in World War I.

A bizarre house filled with an astounding array of collections.

Largest Roman Catholic church in North America.

The granddaddy of English geoglyphs dates back to the late Bronze Age.

The oldest still-operating tavern in the United States was once owned by a pirate.

Abandoned Coast Artillery fort now serves as a graffiti canvas and sightseeing vantage point.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

Elaborate tile work in this railway station tells the story of Portugal.

A hidden three-foot-wide house separates these two regal churches.

This enormous censer uses a pulley system installed over 400 years ago.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

A fantastic Christmas tradition where defecation meets the manger.

The oldest house in Galena, Illinois, now is a reminder of when this city was the world's lead mining capital.

This monolithic statue was erected in honor of Chief Black Hawk (even if it wasn't made to look like him).

It was originally part of a "terrible lizards" collection at the 1964 New York World’s Fair.

This abandoned 19th century orphanage started as a boarding school for children of Civil War veterans.

Arguably the best example of an authentic Dutch windmill in the United States, rivaling its counterparts in the Netherlands.