There are plenty of wonderful panoramic vistas in Edinburgh, but not many are hidden smack in the middle of the Old Town.

A 18th century graveyard and its astonishing cortege of macabre iconography.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

360° views of the city plus five floors of optical illusions and hands-on science.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

These fantastically named natural pools look like something out of a Scottish myth.

Hidden beneath a restaurant, underground tunnels tell the story of Malta’s tragic role in World War II.

This 50-foot-deep sinkhole created in the 14th century is home to rare plants and fungi.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

Enigmatic tombs and cave dwellings on the outskirts of a rural village.

Overshadowed by other, more famous Maltese catacombs, this ancient burial chamber has one of the best examples of a ritual agape table.

The remains of a 1st-century aristocratic Roman town house featuring beautiful well-preserved mosaics.

These lesser-known Maltese catacombs date back over 1,700 years.

A hidden tunnel of bones in one of Malta's oldest churches.

The Jesus tree of Malta bears a striking resemblance to Christ on the cross.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

Stripes of human ashes cover a back lawn in the most sought-after burial grounds in Paris.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.