The last remnants of Fort Pitt also hold the distinction of being the oldest structure west of the Allegheny Mountains.

Sections of the iconic limestone columns have been left uncleaned as a reminder of the city's polluted past.

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

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

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

A jungle in the heart of São Paulo reminds visitors of what Brazil looked like untouched by man.

A mysterious castle built as a monument to lost love.

The last SR-71 ever constructed.

Dubbed the "Blade Runner dragon," this buzzing neon sign is a beloved local icon.

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

The flagship building of an early national restaurant chain is a superb example of terra cotta art.

This award-winning men's bathroom was just too beautiful to not allow women to see.

The site of the one of the most deadly train wrecks in American history.

This replica of the Greek structure is in the heart of Nashville.

At 135 years old and counting, this historic print shop is heaven for poster nerds and music buffs.

The grave of America's 11th president is not in some grand monument but instead it's hidden away on the grounds of the Tennessee Capital.

The awe-inspiring ship from the golden era of cruising has an incomparable history and a reputation as one of the world’s most haunted places.

12,000 sq. ft. museum tracing erotic art from antiquity to modern times.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

An early 20th-century bullring converted into a modern shopping center.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.