Which desert is characterized by its ancient, highly eroded mountains, extreme aridity, and unique populations of desert-adapted flora and fauna, including the Welwitschia mirabilis?

1. It's located along the Atlantic coast of Southern Africa.
2. It's known for its towering sand dunes, some among the highest in the world.
3. Diamonds are found within its coastal regions.
4. The desert's name translates to 'vast place' in the Khoekhoe language.