The Empty Quarter, or Rub' al-Khali in Arabic, is one of the world's largest deserts. Spanning nearly 650,000 square kilometers -- mainly in Saudi Arabia -- it dominates the Arabian Peninsula ...

Deserts cover more than one-fifth of the Earth's land area, and they are found on every continent. A place that receives less than 10 inches (25 centimeters) of rain per year is considered a desert.

An international team of researchers, including scientists from UNIGE, has discovered that the Arabian Peninsula's desert was once shaped by a massive lake and a network of rivers. The Rub’ al-Khali, ...