Agadez is a historical city located on the southern edge of the Sahara desert in Agadez Region in Niger. It was founded in the 14th century AD or the century before that, and then the trans-Saharan trade contributed to its prosperity and growth, and it became the most important city for the Tuareg people. Agadez became the capital of the Sultanate of Agadez in 1449 but was later conquered by the Songhai Empire in 1515. The Sultanate of Agadez then regained its independence after defeating the Songhai Kingdom in 1591.The city has many earthen dwellings and a collection of well-preserved palatial and religious buildings including the Grand Mosque whose minaret is considered the tallest building in the world made entirely of mud bricks. Agadez was inscribed on the UNESCO World Heritage List in 2013, as part of the Historic Centre of Agadez.