  We here study the multi-band properties of a kiloparsec-size superbubble in
the late-type spiral galaxy NGC628. The superbubble is the largest of many
holes seen in the early release images using JWST/MIRI filters that trace the
Polycyclic Aromatic Hydrocarbon (PAH) emissions. The superbubble is located in
the interarm region ~3 kpc from the galactic center in the south-east
direction. The shell surrounding the superbubble is detected in HI, CO, and
Halpha with an expansion velocity of 12 km/s, and contains as much as 2x10^7
Msun of mass in gas that is mostly in molecular form. We find a clear excess of
blue, bright stars inside the bubble as compared to the surrounding disk on the
HST/ACS images. These excess blue, bright stars are part of a stellar
population of 10^5 Msun mass that is formed over the last 50 Myr in different
star formation episodes, as determined from an analysis of color-magnitude
diagrams using a Bayesian technique. The mechanical power injected by the
massive stars of these populations is sufficient to provide the energy
necessary for the expansion of the shell gas. Slow and steady, rather than
violent, injection of energy is probably the reason for the maintenance of the
shell structure over the kiloparsec scale. The expanding shell is currently the
site for triggered star formation as inferred from the JWST 21 micron (F2100W
filter) and the Halpha images.
