This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.

These abandoned grain silos and tunnels are an urban exploration dream.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

A hollow cement depiction of time's inexorable effect on the human body.

A haunting statue called "Eternal Silence" has quite the reputation among visitors with active imaginations.

An enormous park-like oasis, full of famous Chicagoans' graves.

A medieval abbey featured on 'Game of Thrones' that dates back to the 12th-century.

A trail of "Game of Thrones"-themed doors carved from fallen trees from the iconic Dark Hedges.

A beloved upside-down beacon off the coast of Northern Ireland.

The only monument to name all of the passengers and crew who died on the RMS Titanic.

A giant sculpture of the legendary "Salmon of Knowledge" celebrates the return of fish to Belfast's River Lagan.

These barriers stand as stark reminders of Northern Ireland's troubled past.

An Irish cemetery filled with victims of political strife and violent conflict, including the grave of Bobby Sands.

The inscribed stone at Kilnasaggart is a remnant from nearly a millennium ago.

It is said a heartbroken man visited the gap every day to stare blankly out at the sea.

This Italian-style temple replica has been threatening to fall off the Irish coast for hundreds of years.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

Northern Ireland's Brobdingnagian stepping stones.

The atmospheric road was never meant to be so creepy.

A stunning Victorian abbey and walled garden on a lakefront.

This 14th century tower house was once the home of Irish poet W.B. Yeats.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.