The top destination in the Southern Region is Sossusvlei with its monumental dunes, up to 325 m when measured from the base. These star-shaped dunes are a sought-after topic for artists and photographers . Formed by strong multi-directional winds, they are at their highest and most spectacular where the west-flowing Tsauchab River empties itself into the vlei. The warm tints of the sand, ranging from apricot to orange, red and maroon, contrast vividly with the dazzling white surfaces of the large deflationary clay pans at their bases. When it has rained sufficiently in the interior for the Tsauchab River to come down and fill the main pan, flamingos and other aquatic birds are drawn to the area. Lodges in the surroundings for visitors interested in visiting Sossusvlei include the Sossusvlei Wilderness Camp, which offers early morning drives to the vlei. A bird's-eye view of the vlei and its surroundings can be enjoyed from the dizzying heights of a hot-air balloon.