This one-time health resort was used by aristocrats around the world.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

This beautiful, historic church looks like something out of a simpler past.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

The summer tourists on these cliffs are thousands of seabirds.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

This elegant arc of a waterfall marks a religious turning point.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Medicinal spa created with the discharge from a geothermal energy plant.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

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

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.

The deepest metro station in the world.

This unassuming museum's slogan translates to “there is a limit of sadness, anxiety has no limits."

One of the most poignant ruins of the Chernobyl nuclear disaster, the local football team's stadium has been quickly reclaimed by nature.

This attraction was abandoned after the Chernobyl disaster.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

This historic black and white monastery is one of Bulgaria's architectural jewels.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.