Rome's semi-secret peephole vista is also a former Crusader stronghold.

The great Danube river starts here.

Walk through a fairytale in Tuscany.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

The rocks of a certain area of Butte, Montana give off a musical ring when hit.

Extraordinary sculpture garden created by an eccentric English poet.

After a nearly successful attempt on Hitler's life, the conspirators met their fate in the courtyard of this Berlin building.

The world is full of swimming holes, but few compare to Samoa’s idyllic To Sua ocean trench.

A site of natural wonder and flying coconuts in Samoa.

A museum now occupies the mansion in Samoa where the prolific Scottish writer chose to spend the last years of his life.

An unmarked, overgrown path through dense vegetation leads to the largest ancient structure in Polynesia.

"The country that ate itself."

An enormous concrete structure built over a nuclear crater.

An abandoned guano-mining city in the South Pacific.

The ruins of a lighthouse on the island Amelia Earhart never reached.

Amelia Earhart's possible place of death.

A remote coral island with a gristly history of shipwreck, battles, and a horrendous war crime.

A desperate final message left by a POW on the run serves as a memorial for himself and the 97 that died with him.

This industrial area was the dumping ground for massive amounts of trash, some of which washes up as tiny bits of sea glass.

An authentic replica of an Asian temple and garden hidden amongst the natural beauty of Hawai'i.

This ancient Hawaiian henge may have been an early star chart.

Running since 1864, this clock has yet to be wound, one of the longest-running science experiments known.