This striking observation tower shaped like a spinnaker sail is the newest icon in historic Portsmouth.

This star-shaped artillery fort protected the mouth of the Thames from the 16th century to the Second World War.

The castle still holds traces of the abandoned Roman fort it was built atop.

This single room has survived the centuries with almost no deterioration.

An antique horse-drawn hearse provided French luxury for the dead in this Texan town.

Colorful curls of hand-blown glass form a captivating tower in San Antonio's Central Library.

The story behind the mysterious symbol painted in front of the historic university's famous Rotunda.

This iron and wood Civil War city-ship was the first vessel to be sunk by an electrically detonated torpedo.

An eerie and beautiful group of columns mark the site of a grand mansion lost to time and fire.

A grandiose octagonal home crowned by a large dome stands out among the antebellum mansions.

A remarkable medieval structure born from a 14th-century disaster.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

Cryptic messages embedded in the New York City sidewalk.

This big empty pig is a nostalgic throwback to mid-20th-century Texas barbecue.

A unique tribute to the millions of animals who served and died for the British military.

A wall of chewing gum moonlights as collective art.

Follow the original medieval paths that wind through this intriguing section of the city.

The "Prussian Versailles" that is as glorious today as when it was built.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A former fisherman's hut deemed too small for habitation is now a delightful tourist draw.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

Cold war icon and onetime "hole" in the iron curtain.

A slice of central Asia in the middle of Berlin.

A fascinating insight into daily life in the Eastern Bloc.