The universe is filled with cosmic microwave background radiation at 2.73 K (Figure 1). It is a relic of the "fire-ball" that the universe once underwent shortly after its birth. This is the lowest-temperature black-body radiation that mankind has ever witnessed. Where can we expect highest-temperature black-body radiations? An answer may be found in the explosion of massive stars. Stars more massive than 10 solar masses that are destined to die as type II supernovae (Figure 2) evolve to form an onion-like pre-supernova structure consisting of multi-layers of hydrogen, helium, carbon, silicon, and the iron core as dominant elements. The gravitational collapse of the iron core triggers the explosion. Typically energy of about 1% (˜10 51 erg) of the gravitational energy is sufficient to explode massive stars, blowing off the outer layers and leaving neutron-stars (black-holes) as remnants. During the supernova explosion, the shock wave propagates the outer layers and heats material behind it, making, for example, the O-Ne-rich layers ideal heat baths filled with black-body radiation at multi-billions of Kelvin cc.