An ancient Viking runestone hidden in plain view in Stockholm's old town.

Several cannonballs of mysterious origins decorate two buildings in Stortoget's main square.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

Sweden's oldest animated sign is still lighting up the skyline today.

Outside a Viking museum sits a modern-day runestone made by a Swedish runemaster using traditional methods.

It houses the remains of a 17th-century version of the Titanic.

Swedish skyscraper with a 90° twist.

This platform is now a memorial dedicated to those who were deported during the Holocaust.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

Tiny memorials honor individual victims of the Holocaust.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

One of the world's heaviest musical instruments towers within a popular urban park.

One of downtown Berlin's last reminders of its Communist past.

A restaurant and observation deck built in a unique broadcasting antenna.

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

Cold war icon and onetime "hole" in the iron curtain.

A monument to the man who almost killed Hitler.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

For patriotic Russians, this memorial honoring the Soviet soldiers who died liberating Berlin in 1945 is the most sacred location outside of Russia.

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.