An unusual round church in London with a Templar past.

Ship-sized kinetic sculptural fantasy.

The largest of London's subterranean rivers and once a mad, bad center of London life.

This South London cemetery holds the remains of more than 15,000 people.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

Launch site for nuclear war against Western Europe.

The remains of Crystal Palace Great Exhibition of 1851.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

Controversial site of what could be Europe's first pyramid.

Hundreds of thousands of concrete bunkers crowd Albania long after the fall of Communism.

A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

Structure built from the skulls of vanquished foes.

A marvel of Byzantine engineering under the streets of Istanbul.

Sofia's legislative center is continuously reinventing itself.

Ruins of an early Roman Christian church dating back to the 4th to 5th centuries.

An homage to the medieval rulers of Bulgaria.

Massive, unfinished broadcasting station stands as a monument to the fall of communism.

Eastern Bloc nostalgia, anybody?

"Holy Wisdom" overlooks the city that became its namesake.

"Unity, Creativity, Beauty."

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

Said to be the only museum in the world dedicated to the most classic of all blooms, the rose.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.