WARNING: Since July 2012, Gao is under the control of Islamist rebels, who have imposed strict sharia law on the areas of Mali they control. Travel should not be considered to Gao at the moment for any reason. More info can be found in the warning at the top of the Mali page. 
Gao is a small city of 65.000 inhabitants located in the Gao region of Mali.
Askia Tomb. Constructed in 1495 by Songhai emperor Askia Mohamed Toure, the Askia Tomb (known locally as the Askia Mosque) is a mud-brick pyramid designed to look like the Great Pyramids of Egypt, which Mohamed saw on his pilgrimage to Mecca. Today it is still used as a mosque and is a UNESCO World Heritage site. (Note: This has reportedly been destroyed or been significantly damaged/defaced by Islamist rebels for being 'idolatrous' during their occupation of Gao in 2012. These are the same people responsible for the destruction of Timbuktu's shrines.)
Traditional markets. The vegetable and meat markets are in the center of town beside the river. They feature the usual assortment of produce and spices as well as blocks of salt mined in the far north of Mali. The Marche Washington, down the road towards the Askia Tomb, sells clothing and fabric and is full of tailors at work.
La Dune Rose A giant sand dune across the river from Gao, named for its glowing pink color at sunrise and sunset. Best reached by pirogue. The top has beautiful views of the surrounding landscape, especially after the rainy season.