Geometric group theory and 3-manifolds hand in hand: the fulfillment of Thurston's vision
In the late 1970s, Thurston revolutionized our understanding of 3-manifolds. He stated a far-reaching geometrization conjecture and proved it for a large class of manifolds, called Haken manifolds. He also posed 24 open problems, describing his vision of the structure of 3-manifolds.
Pieces of Thurston's vision have been confirmed in the subsequent years. In the meantime, Dani Wise developed a sophisticated program to study cube complexes and, in particular, to promote immersions to embeddings in a finite cover. Ian Agol completed Wise's program and, as a result, essentially all problems on Thurston's list are now solved. In these notes I will outline a proof that closed hyperbolic 3-manifolds are virtually Haken.