This Communist-era residential block is one of the longest residential building in Europe.

Modern art commemorates one of the first military actions of World War II.

This picturesque castle in Poland has a rich history, including a legend that ties it to lost Incan treasures.

This 13th century Gothic brick castle is the largest in the world by surface area.

In northeastern Poland, the ruins of a massive granary overlook the Narew River.

An abandoned Jewish sanatorium is tucked within the woods of Poland.

A World War II torpedo launch station abandoned off the Polish coast.

A striking public sculpture representing the period of martial law in Communist Poland.

A haunting deserted hotel is a favorite with artists and photographers.

These massive moving sand dunes have swallowed an entire village and are still on the run.

Naturally formed rock city in Poland.

This imposing 20th-century castle was abandoned before it was ever completed.

This hidden collection of everyday objects illustrates life within communist Poland.

An abandoned Nazi explosives plant founded by the inventor of dynamite is now an underground museum.

Visiting dignitaries and Hollywood stars once stayed at this 1920s hotel, alongside ghosts that are said to haunt its corridors.

A fascinating little museum all about the rich history of Peru’s famous plant.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

This extensive collection covers thousands of years of Polish military history.

This hilltop ruin is of the hundreds of stone columns built in tribute to the first German chancellor.

The site of the first battle of World War II.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

The underground sanctuary of a mysterious ancient cult.