Which Australian desert is known for long parallel dunes including Big Red?

The Simpson Desert is the Australian desert known for long parallel dunes, including the landmark dune called Big Red. It occupies central Australia across parts of the Northern Territory, Queensland, and South Australia.

The Simpson is an erg, a desert dominated by wind-shaped sand. Its dunes generally run north–south and can continue in parallel for great distances. Vegetation helps hold many of the ridges in place, while differences in wind exposure produce gentler western slopes and steeper eastern faces. The sand ranges from pale gray to vivid red, with iron oxides contributing to the deeper colors.

Big Red’s formal name is Nappanerica, and it rises about 40 meters. The desert is also underlain by the Great Artesian Basin, so groundwater reaches the surface at mound springs such as Dalhousie Springs. These springs provide unusual wetland habitats in an otherwise extremely dry environment.

The Simpson is often confused with the Gibson, Tanami, or Great Sandy deserts, but its combination of parallel dune fields and Big Red is distinctive. Travelers commonly cross it from west to east, when prevailing winds and dune slopes make the journey easier.