Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

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

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

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

A statue honors the children who fought Nazis in Poland.

The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

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

Special benches that play Chopin's music are scattered throughout his native city.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

Op-art architecture designed for happiness.

This unique Lady Liberty is one of the only examples of the figure sitting down.

World's largest crossword puzzle spans the side of a towerblock, its clues scattered throughout the city.

Transmission tower outfitted with large crossbars that dampen wind-induced oscillations.

The spectacular Roshen Fountain show lights up the night sky all summer long, until it "hibernates" under the ice waiting for spring to come.

The largest catacomb system in the world.

Padlocks cover this rickety footbridge with love.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

Slather on the history at an exhibition dedicated to this Russian luxury.

Thousands of biblical and pagan images are carved into this small 12th-century church.

A modern tower, symbolizing the legend of a golden egg on top of the tree of life.

Iconic pyramid from famed British architect Norman Foster designed to represent all of the world's religious faiths.

When you've got to go, you've got to go.

An Art Nouveau building covered in animal gargoyles and grotesques.