  Extreme Black holes are an important theoretical laboratory for exploring the
nature of entropy. We suggest that this unusual nature of the extremal limit
could explain the entropy of extremal Kerr black holes. The time-independence
of the extremal black hole, the zero surface gravity, the zero entropy and the
absence of a bifurcate Killing horizon are all related properties that define
and reduce to one single unique feature of the extremal Kerr spacetime. We
suggest the presence of a true geometric discontinuity as the underlying cause
of a vanishing entropy.
