From a really excellent gallery of hominid busts in the National Museum of Natural History; Washington, D.C.:
Homo heidelbergensis was an early human species, living some 700,000 to 200,000 years ago. It’s thought to be the direct ancestor of both Neanderthals and Homo sapiens, with Neanderthals diverging from H. heidelbergensis about 300,000 years ago, and H. sapiens diverging 100,000 to 200,000 years ago. H. heidelbergensis was quite a step forward from its predecessors — the species was capable of controlling fire, and was the first to build simple shelters and hunt large game.
H. heidelbergensis was first discovered in 1908, in the form of a nearly complete jaw found in the Rösch sand pit near Heidelberg, Germany. It took quite a while to find more than just this first mandible, so recognition of H. heidelbergensis as a distinct species was slow in coming (and is largely, but still not universally accepted).