Replica wormholes and the information paradox

I will review recent progress on the black hole information puzzle involving the appearance of "islands" in the black hole interior. The islands arise from the replica trick used to calculate the entropy of Hawking radiation. This entropy receives large non-perturbative corrections from gravitational instantons called replica wormholes, which connect multiple copies of the black hole through their interiors. Islands also appear in crunching cosmologies, leading us to revisit holography in this setting.