The remains of the last Bosnian fortress to fall to the Ottomans are still standing.

A high school astronomy enthusiast designed this model of our solar system to be traversed on foot.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

This piece of Australian modern art is part joke and part history.

This museum was invented in a novel before being made real by the author.

More than half of this Indian palace is drowned but it looks all the more spectacular for it.

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

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

In this historic region, homes and churches are carved into ancient volcanic rock formations.

A model of a dinosaur that was named for Andrew Carnegie stands outside the museum that also bears his name.

This micro-nation may be some sort of prank, but its constitution sure seems official.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

The Habsburgs' royal collections of art and wonders.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

There aren't too many operational funiculars around, but Pittsburgh has two!

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

This dark, damp, perilous tunnel is the only passage from north to south Tajikistan.

The most metal church of all time was built in record time because of an international, pious pissing contest.

1513 Turkish world map, full of European state secrets and snarky commentary.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.