Constantine, also spelled Qacentina or Kasantina, is the capital of Constantine Province in north-eastern Algeria. During Roman times it was called Cirta and was renamed "Constantina" in honour of emperor Constantine the Great. It was the capital of the same-named French département until 1962.

Regarded as the capital of eastern Algeria and the centre of its region, there are museums and important historical sites around the city. It is often referred to as the "City of Bridges" due to the numerous picturesque bridges connecting the mountains the city is built on.