  Quantum gravitational corrections to black holes are studied in four and
higher dimensions using a renormalisation group improvement of the metric. The
quantum effects are worked out in detail for asymptotically safe gravity, where
the short distance physics is characterized by a non-trivial fixed point of the
gravitational coupling. We find that a weakening of gravity implies a decrease
of the event horizon, and the existence of a Planck-size black hole remnant
with vanishing temperature and vanishing heat capacity. The absence of
curvature singularities is generic and discussed together with the conformal
structure and the Penrose diagram of asymptotically safe black holes. The
production cross section of mini-black holes in energetic particle collisions,
such as those at the Large Hadron Collider, is analysed within low-scale
quantum gravity models. Quantum gravity corrections imply that cross sections
display a threshold, are suppressed in the Planckian, and reproduce the
semi-classical result in the deep trans-Planckian region. Further implications
are discussed.
