Bayanzag is a formation of red sandstone cliffs located in Bulgan sum, Umnu-Gobi province. The name, Bayanzag, is derived from the saxaul tree in the Gobi desert, whose wood is coarse and bark is spongy.

An American paleontologist Roy Chapman Andrews led an expedition in the South of Mongolia, and discovered the first ever dinosaur eggs in the world along with hundreds of dinosaur skeletons at Bayanzag in 1922. The expedition stopped due to harsh sandstorm in the south.

When the sun shines right at the red sandstone cliffs, it looks almost as if the cliffs were on fire; hence Bayanzag is sometimes called the flaming cliffs as well.