This Gothic castle-like portal is a testament to the amazing craftsmanship of the navvies who built the railway tunnel.

Moss and stone turn this waterfall into an otherworldly liquid veil.

These particularly resplendent rodents are the state animal of Maharashtra.

A spiritual sanctuary in a natural cave.

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

This spectacular bridge supported by two gigantic hands looks like something out of a fantasy universe.

England’s ancient oak tree has such an impressive girth, people have been hosting parties within the hollow trunk for centuries.

Japan's largest area of "pink moss" turns the hillside bright pink every spring.

Bali's remote "gateway to heaven" is one of the most sacred places on the island.

Hidden in the shadow of a rocky fortress is one concubine’s long-forgotten legacy.

Happy harbor seals frolic and snooze on this warm, sandy stretch of coast.

The medieval network of canals hidden underneath the city is opened to explorers each year.

This modern castle sat empty for decades before a fire inspired its builders to complete its luxury halls.

The rogue roots are gradually consuming some of the historic marble grave markers.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

A display of magnificent stained glass windows is the first exhibit of its kind.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

What was once the second largest steel mill in the US is now a sprawling complex of modern ruins.

This unauthorized stone mermaid was secretly carved out of public stone before being permanently preserved.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

These sub-farmland caves are home to a majestic stalactite known as the "Crystal King."