This long unused shot tower on the Mississippi remains a point of pride for a small city in Iowa.

One of the greatest heroes of the Titanic tragedy came from humble beginnings to this beautiful home.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

A striking 12th-century-style castle built on the edge of a cliff.

The homestead of American patriot John Adams.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

This groundbreaking 16th-century map is known as "America's birth certificate."

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

The world's largest reflecting pool is just two centimeters deep.

One of the best-preserved medieval streets in Europe.

This 11th-century Greek monastery has renowned mosaics and relics of a brutal past.

This medieval "painted village" is famous for its geometric facades.

The mark of the Devil's horns on a marble column in Milan.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

A once-thriving hotel in the Swiss Alps couldn't compete with climate change.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

The Swiss artist's bulbous and overgrown shape-shifting sculpture controversially graces the center of Bern.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

Swiss vineyards in a UNESCO heritage site.

Traversing steep Alpine slopes, this engineering marvel is one of the longest and highest funiculars in the world.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.