A vast Communist-era exhibition space in the Bulgarian capital.

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

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

A striking symbol of the Bulgarian capital.

This historic black and white monastery is one of Bulgaria's architectural jewels.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

This exquisite, alienesque piece of Soviet architecture is being threatened by modern shopping malls.

A fortress built to pacify local uprising that had a stint as a Nazi concentration camp before becoming a five-star hotel.

This 1000 year old relic-filled cave monastery and UNESCO World Heritage Site also hosts an amazing micro-miniature museum.

The deepest metro station in the world.

One of the largest museums in Ukraine remembers the story of the German-Soviet War in iconic, brutalist style.

340-foot statue built to honour the Heroes of the Soviet Union.

A reconstructed medieval gateway that was the magnificent entrance to the capital city dating back to 1037.

Two gilded cherubs perched on a church bell tower have been reminding visitors of the finitude of life since 1760.

An ancient water supply dating back almost 500 years can still be found standing in East Sussex.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Go inside to really appreciate this 500-year-old technological masterpiece.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

A tiny replica of the iconic London landmark hides on the side of the steel structure.

A monument to the conquistador became increasingly controversial in the very city that he founded.

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

This bullring in Lima is the oldest in the Americas and the second-oldest in the world.

The elaborate crypt where Peruvian heroes of the War of the Pacific were laid to rest.

Situated on a sacred Inca site, this 16th-century cathedral took nearly 100 years to build.