The evocative ruins of a 1,000-year-old hill fort lie within a popular tiger reserve.

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

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

1513 Turkish world map, full of European state secrets and snarky commentary.

A spectacular rainbow of stained glass makes the "Pink Mosque" one of the most beautiful in Iran.

Stunning ruins of what was once the center of one of the greatest empires in East Africa.

This dramatic sea spire is home to the world's rarest insect and is part of the lost continent of Zealandia.

Once the path of a railway tunnel, now home to thousands of glowing insects.

Australian Lake set aglow by Noctiluca Scintillans.

An Australian lake whose pink hue defies scientific explanation.