Gao's premier tourist attraction is a sunset trip to La Dune Rose, known locally as Koïma, a wonderful sand dune on the right bank of the Niger, visible from town. As it turns pink with the setting sun, there is magic in the air, not least because it was once believed by locals to be the home of magicians.
If you're coming here (only possible from September to February when water levels allow), consider also hiring a pirogue to drift further along the river as the dunes come alive. Upstream at Quema and Hondo (a three-hour trip) there are more stunning dunes, while you're almost guaranteed hippo sightings at Tacharan.