The ornate miniature mansions were built for Istanbul's feathered residents.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

A memorial museum to the political prisoners who were held at Sighet Prison, once one of the most feared places in Romania.

This memorial to the victims of the Romanian Revolution of 1989 is often compared to a potato on a skewer.

Romania's triumphal arch looks out over Bucharest.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

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

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

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

This Transylvanian church has changed its denomination four times.

A space dedicated to contemporary art and culture, co-chaired by fashion icon Miuccia Prada.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

This nightlife venue and cultural center keeps a unique Ethiopian musical tradition alive in the nation’s capital, but breakneck urban development threatens to shut it down.

This glass wall is gradually filling up with paper cranes, in honor of Hiroshima’s past and dedication to its future.

An eerie reminder to the horrors of World War II.

Peace Park and the Atomic Bomb Dome.

A plaque marks the site directly below the mid-air detonation of the atomic bomb over Hiroshima.

When this clock strikes a certain time, puppets showcase a story of life in Edo Japan.

A 20-meter (65-foot) robot towers over Tokyo Bay.

This Buddhist temple is home to the graves of the Japanese national legends, the 47 Ronin.

Not quite the menace it once was, this monster still has some chops.

The legendary birthplace of the Japanese maneki-neko is dotted with hundreds of lucky beckoning cats.