The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

Huge winged monument in the United Kingdom.

The largest timber structure in Europe.