Present knowledge about the nature of spacetime singularities in the context
of classical general relativity is surveyed. The status of the BKL picture of
cosmological singularities and its relevance to the cosmic censorship
hypothesis are discussed. It is shown how insights on cosmic censorship also
arise in connection with the idea of weak null singularities inside black
holes. Other topics covered include matter singularities and critical collapse.
Remarks are made on possible future directions in research on spacetime
singularities.Comment: Submitted to 100 Years of Relativity - Space-Time Structure: Einstein
and Beyond, A. Ashtekar (ed.