Which North African desert includes the Great Sand Sea?

The North African desert that includes the Great Sand Sea is the Libyan Desert. It forms the eastern part of the Sahara and covers a huge expanse across Libya and Egypt, with smaller extensions toward Sudan and Chad. In Egypt, the same broad region is often called the Western Desert because it lies west of the Nile.

The Libyan Desert is not one uniform field of dunes. Its landscapes include rocky hamadas, gravel plains, mountain massifs, deep depressions, oases and several major sand seas. The Great Sand Sea straddles the Egypt–Libya border, while the Calanshio, Rebiana, Murzuq and Ubari sand seas occupy other parts of the wider desert. The oasis of Siwa lies near the Great Sand Sea in Egypt.

The region is also known for Libyan Desert glass, a naturally occurring yellow-green silica glass found near the Egyptian-Libyan border. It may have formed from an ancient meteorite impact or airburst, and a piece was reportedly used in a jewel associated with Tutankhamun. The Nubian Desert is nearby but lies mainly east of the Nile, so it is not the best answer here.