abstract: I will talk about the pro-etale fundamental group, which is a refinement of Grothendieck's etale fundamental group constructed using the pro-etale topology. In particular, I will explain why the pro-etale fundamental group is better behaved for singular varieties: it detects all lisse l-adic sheaves through its representation theory (which fails for the groups constructed in SGA on the simplest non-normal varieties, such as nodal curves). This is joint work with Peter Scholze.