The Bardo, which focuses on the prehistory of Algeria, is one of the best museums in Algiers. The collection is well-displayed with videos, models and excellent diagrams and information panels (in French) that reveal how the climate and environment of the region have changed over the eons and how that has affected human and wildlife development. There are lots of fossils, neolithic pottery, rock carvings and examples of Neanderthal paintings from the Sahara.
Emerging from the museum, head up the tiled steps to the 'Summer Palace', an Ottoman-era palace of courtyards, fountains and sub-tropical gardens. It's within the same compound as the museum and included in the entry price.