An abstract monument to a symphonic composer.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

A subterranean house of worship carved right out of the bedrock.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

Moscow's imposing monument to the Space Age.

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

What looks like a birch tree smushed between two pieces of glass often confounds commuters.

Sweden's first electric elevator remains hidden within a fortress-like building.

Sound travels strangely in this underground whispering gallery.

The Swedish flag over this small naval fort signals that the nation is at peace.

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

This giant subway sculpture celebrates the fruit that inspired the theory of gravity.

Located in an old church, this brewery produces a different kind of holy water.

When this 18th-century observatory's meridian was moved, it set Sweden's time back by 0.04 seconds.

A golden plaque marks the site of the mysterious unsolved assassination of the former Swedish prime minister.

This giant crucifix is like U2's Joshua Tree for Swedish death metal fans.

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

A former suicide bridge is now accumulating symbols of love instead of a body count.

Stockholm's narrowest alley is barely over two feet wide.

Early habitat dioramas and home of the elusive gaff, the skvader.

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.

A man has revenged his true love's betrayal through tears and stone genitalia.

This homeless brass fox tugs at your heartstrings from the foot of a Stockholm bridge.

Stockholm's deepest subway station is also a stunning ecological wonder.