The Herschel/HOBYS key program allows to statistically study the formation of 10−20 M
⊙ stars. The IRAM/W43-HERO large program is itself dedicated to the much more extreme W43 molecular complex, which forms stars up to 50 M
⊙. Both reveal high-density cloud filaments of several pc3, which are forming clusters of OB-type stars. Given their activity, these so-called mini-starburst cloud ridges could be seen as “miniature and instant models” of starburst galaxies. Both surveys also strongly suggest that high-mass prestellar cores do not exist, in agreement with the dynamical formation of cloud ridges. The HOBYS and W43 surveys are necessary steps towards Galaxy-wide studies of high-mass star formation.