The Grand Prismatic Spring in Yellowstone National Park.

The Grand Prismatic Spring in Yellowstone National Park.

The Grand Prismatic Spring in Yellowstone National Park.

Oil and water do not mix

Oil and water do not mix

Oil and water do not mix

Thousands of birds take off together at the Snettisham Nature Reserve in England

Thousands of birds take off together at the Snettisham Nature Reserve in England

Thousands of birds take off together at the Snettisham Nature Reserve in England

Hot and cold in Ukraine

Hot and cold in Ukraine

Hot and cold in Ukraine

Palmyra, Syria

Palmyra, Syria

the largest set of Roman ruins in the world – Palmyra, Syria