About Hrushovski and Loeser's work on the homotopy type of Berkovich spaces

Those are the notes of the two talks I gave in april 2013 in St-John (US Virgin Islands) during the Simons Symposium on non-Archimedean and tropical geometry. They essentially consist of a survey of Hrushovski and Loeser’s work on the homotopy type of Berkovich spaces; the last section explains how the author has used their work for studying pre-image of skeleta.