In the magical time surrounding sunset, the white sands of White Sands National Monument glow with a radiant essence. To emphasize and contrast the rich hues, the lengthening shadows add extra depth and mystery to the dunes. Then, for a few moments, it gets even better--the prominent ridge of the San Andreas Mountains turns comparatively black, acting as a rigid divider between the pale glows on the sands, and the pastel expanse that becomes the sky. Simply amazing.
A tip for dune landscape: When travelling to dunes, take a long lens--I'd recommend 135mm - 250mm. This allows you to keep the interesting details interesting, while not losing them in expansive foregrounds or skies.