A discarded movie prop that was the original monolith for "2001: A Space Odyssey."

This unassuming building produced some of the world's most famous bells.

A fascinating aviation museum where you can chat with the veterans who once flew the aircraft on display.

The unbelievably opulent home built for an infamous newspaperman.

A building so large that it has its own weather.

This singular art museum in São Paulo is unique inside and out.

Millions of numbers carved in glass represent the tattoos forced upon victims.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

The topiary maze at the Habsburg hunting lodge.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

The shell of a medieval fortress offers commanding views of the area it once protected.

Double spiral staircases are not unheard of, but they are very rare.

This statue once earned the distinction as one of the "Three Major Disappointments of the World."

The largest pool at its elevation sits on top of one of the most expensive resorts in the world.

Singapore's landscaping project is home to 18 incredible Supertrees.

A Norwegian-born sculptor created these soaring guardian angels at the entrance to Hoover Dam.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

An exotic wildlife habitat right off The Strip.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

Macabre astrological automaton clock dating to the late 1400s.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

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.