A moody and picturesque riverside ruin overgrown with vegetation.

Modern sundial uses ancient methods to tell time and date perfectly.

The 19th-century pharmacy (now a used bookstore) was featured in James Joyce’s "Ulysses," and has changed very little to this day.

The enchanting archway is the only surviving portal into Dublin's lost medieval wall.

An 80-year-old plane tree is devouring an iron bench at Ireland's oldest law school.

An Irish church where an 800-year-old mummy is reaching out of his coffin as if to shake hands.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.

A small town Romanian cemetery filled with darkly humorous gravestones.

A collection of items from a way of life that no longer exists.

Moss and stone turn this waterfall into an otherworldly liquid veil.

A giant portrait of an ancient king looms over the river.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

This solitary monastery may hold the remains of Vlad the Impaler (but probably not).

This massive underground salt mine now holds a sci-fi theme park in its depths.

Gigantic Romanian salt mines used to heal respiratory conditions.

Where the lovelorn find a home for their sentimental keepsakes.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

Before building her own tombstone, an untrained artist created a concrete menagerie in her garden.

Mysterious painted skulls in Moravia.

Artfully arranged bones of 5,800 Austrians.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

The shell of a medieval fortress offers commanding views of the area it once protected.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.