"Руб-аль-Халі" (Rub' al Khali), also known as the Empty Quarter, is one of the largest sand deserts in the world. It spans parts of four countries: Saudi Arabia, Oman, Yemen, and the United Arab Emirates. The desert covers approximately 1,000 kilometers (620 miles) in length and is characterized by vast sand dunes, some reaching heights of over 250 meters (820 feet). The climate in the Rub' al Khali is extremely arid, with very little rainfall and high temperatures, often exceeding 50°C (122°F) in summer. Despite its harsh conditions, the desert is home to unique flora and fauna adapted to survive in such an environment, including various species of lizards and rodents.