These ominous lava formations were said to be an entrance to the netherworld so of course they inspired a famous metal band.

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

The oldest inn in England served brew to the crusaders.

These strikingly barren, rolling red hills were caused by bad farming practices.

One of the largest underground systems runs under Canada's largest urban center.

This seemingly cursed monument is dedicated to one of Canada's great war heroes.

This natural wonder is disappearing at an alarming rate.

The mastermind behind this palatial hotel perished on the Titanic weeks before its grand opening.

Only six people can sit inside this delightfully quaint sanctuary.

This impressive working clock made of 16,000 plants changes its flowers twice a year.

A fantastic place to see murals, and an important location in the history of Toronto's legal street art scene.

An abandoned 1970s theme park that has been turned into a space for waterfront walking.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.

Vast stretch of tide-pools with a unique Moroccan charm.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

Op-art architecture designed for happiness.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The final resting place for the remains of 143 Habsburg royalty.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

This ancient jade mask depicting the Zapotec bat god was found in the ruins of the pyramids of Monte Alban.

This strange sculpture of a menacing skull surrounded by sun rays was discovered at the foot of the Pyramid of the Sun.

This museum houses two of Mexico's most impressive Aztec monoliths.

The courtyard of this small Marinid madrasa is a dazzling example of intricate Islamic architecture.

The oldest known university in the world is in Fez, Morocco.