  The black hole information paradox forces us into a strange situation: we
must find a way to break the semiclassical approximation in a domain where no
quantum gravity effects would normally be expected. Traditional quantizations
of gravity do not exhibit any such breakdown, and this forces us into a
difficult corner: either we must give up quantum mechanics or we must accept
the existence of troublesome `remnants'. In string theory, however, the
fundamental quanta are extended objects, and it turns out that the bound states
of such objects acquire a size that grows with the number of quanta in the
bound state. The interior of the black hole gets completely altered to a
`fuzzball' structure, and information is able to escape in radiation from the
hole. The semiclassical approximation can break at macroscopic scales due to
the large entropy of the hole: the measure in the path integral competes with
the classical action, instead of giving a subleading correction. Putting this
picture of black hole microstates together with ideas about entangled states
leads to a natural set of conjectures on many long-standing questions in
gravity: the significance of Rindler and de Sitter entropies, the notion of
black hole complementarity, and the fate of an observer falling into a black
hole.
