  Moir\'e superlattices in van der Waals heterostructures provide a tunable
platform to study emergent properties that are absent in the natural crystal
form. Twisted bilayer transition metal dichalcogenides (TB-TMDs) can host
moir\'e flat bands over a wide range of twist angles. For twist angle close to
60{\deg}, it was predicted that TB-TMDs undergo a lattice reconstruction which
causes the formation of ultra-flat bands. Here, by using scanning tunneling
microscopy and spectroscopy, we show the emergence of multiple ultra-flat bands
in twisted bilayer WSe2 when the twist angle is larger than 57{\deg}. The
bandwidth, manifested as narrow tunneling conductance peaks, is estimated less
than 10meV, which is only a fraction of the estimated on-site Coulomb repulsion
energy. The number of these ultra-flat bands and spatial distribution of the
wavefunctions match the theoretical predictions incredibly well, strongly
evidencing that the observed ultra-flat bands are induced by lattice
reconstruction. Our work provides a foundation for further study of the exotic
correlated phases in TB-TMDs.
