2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/132796With HST, colour-magnitude diagrams (CMDs) can be obtained for young star clusters well beyond the Local Group. Such data can help constrain cluster ages and metallicities, and also provide a reference against which intermediate- and high mass stellar models can be compared. Here, CMDs are presented for two massive (>10^5 Msun) clusters and compared with Padua and Geneva isochrones. The problem of the ratio of blue to red supergiants is also addressed.4 pages, incl. 2 figures. To appear in the proceedings of the 41st ESLAB Symposium, "The impact of HST on European astronomy", ed. G. De Marchi & F. D. Macchetto (Berlin: Springer), in pressAstrophysicstext