 The phase diagram of hydrogen has been studied extensively for decades, but until now it was unclear what would happen when hydrogen was compressed past 500 gPa. Using AB-initio molecular dynamics and path integral simulations, researchers have found that a new atomic phase exists beyond 2-tpa, giving rise to a re-entrance solid liquid transition before entering the Weiner crystalline phase of protons. This discovery extends the known phase diagram of dense hydrogen, putting metallic hydrogen into the same category as lithium and sodium. This article was authored by Hua Weigeng and Kewu.