An ethereal glowing blue ocean cave in Croatia.

The remnants of this unusual bridge await an uncertain fate.

The best place for scenic views of the DMZ and North Korea.

Looking strangely like Rome's Colosseum, this unfinished tower has dominated the skyline for over 100 years.

Where a Japanese government official issued transit visas to Jews fleeing from Nazi-occupied Poland.

Medieval village and microminiature museum.

A 1:2 billion-scale solar system leads visitors into this German university town.

This 19th-century Hamptons windmill was once home to modernist painter Agnes Pelton.

A 100-plus-year-old mill transformed into a hotel and restaurant.

A memorial honoring those who perished in one of the worst construction disasters in U.S. history.

The "Kill Bill Church" was transformed into a place of worship after a long Hollywood history.

The world’s first dedicated cloud observation platform.

A tribute to the hard-working men and women of Grumman, who crafted F-14 fighter jets.

England's most famous front door has an accidental doppelganger.

Yugoslavia's biggest underground airport lies in ruins.

Rare signs of the former Soviet Union in the Caribbean, though not where you'd expect them.

Like something out of a pulp adventure, this abandoned plane wreck is slowly being retaken by the Caribbean jungle.

This abandoned airplane hanger is said to have once been a top secret launch facility.

This soviet pilot's graveyard is filled with headstones made of airplane fins.

You can walk through the first Boeing Air Force One, which famously carried JFK's casket from Dallas back to D.C.

Down the road from where the Wright brothers lifted off is another flight tribute practically hidden from sight in the woods.

An inconspicuous suburban street corner is the site of San Diego's worst air disaster.

An ideal location for plane spotting in British Columbia.

This former Soviet military base has over 10 original aircraft and an enormous amount of memorabilia on display.