The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

A monumental underground karstic wonderland is also the water source for over a million citizens of Beirut.

This now-defunct synthetic fuel plant was once a major cog in the Nazi war machine.

The center of this Polish border town was so thoroughly wiped out in World War II that only the foundations remain.

This formerly-prosperous Silesian mining town was completely demolished in the late 1960s and early 1970s as an attempt to cover up a secret Soviet uranium mine.

The majority of the highest mountain in Poland is actually located in a different country.

The first, and perhaps only, monument dedicated to Wikipedia.

In the midst of a living monument to Soviet social engineering, Polish Catholics built this church by hand.

The giant statue and its model solar system honor the native Pole who declared that the Earth revolves around the Sun.

One of the largest amphitheaters in Europe is a former Nazi gathering place that still stands today.

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

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.

A mysterious structure left behind on the Polish mountainside, sometimes called "Hitler's Stonehenge".

Order “Proletariat’s Cutlet” at this communist-themed restaurant allegedly once visited by Lenin.

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

A peculiar family mausoleum built by a German nobleman captivated by the occult.

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

A national collection of Communist-era musical posters.

A memorial to the beloved brown bear that served in the Polish army during World War II.

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

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

This man-made mound monument was built out of soil from all across the Polish empire.

This 700-year-old structure is one of the most unique architectural and historic monuments in Gdańsk.

A hidden art gallery in an abandoned Warsaw fort.