  Microscopic black holes explode with their temperature varying inversely as
their mass. Such explosions would lead to the highest temperatures in the
present universe, all the way to the Planck energy. The possibility that a
quasi-stationary shell of hot matter surrounds these black holes has recently
been proposed and studied with relativistic Boltzmann transport equations and
with relativistic viscous fluid dynamics. For example, a black hole with a mass
of 10$^{10}$ g has a Hawking temperature of 1 TeV, a Schwarszchild radius of
1.6$\times10^{-5}$ fm, a luminosity of 7$\times10^{27}$ erg/s, and has less
than 8 minutes to live. It is an outstanding theoretical challenge to describe
the conditions exterior to such microscopic black holes and a great challenge
to finally detect them in the new millennium.
