All massive stars form in hubs: all sources with a luminosity L ≥ 10⁵ L_⊙ in the inner Milky Way and located at a distance of <5 kpc are found to be HFSs. All hubs are marked by green circles. Clumps (with L ≥ 10⁵ L_⊙) that arenot found to be hubs (blue triangles) are located farther than 5 kpc because the 18′′ beam resolution of the data is insufficient to resolve these structures. The yellow line at L = 10⁴ L_⊙ indicates the Eddington ratio at which radiation and gravitational pressures become roughly equal; at <2 kpc, all objects above this luminosity are hubs, demonstrating that massive stars preferentially form in hubs.