  The crystal structure of a material creates a periodic potential that
electrons move through giving rise to the electronic band structure of the
material. When two-dimensional materials are stacked, the twist angle between
the layers becomes an additional degree freedom for the resulting
heterostructure. As this angle changes, the electronic band structure is
modified leading to the possibility of flat bands with localized states and
enhanced electronic correlations. In transition metal dichalcogenides, flat
bands have been theoretically predicted to occur for long moir\'e wavelengths
over a range of twist angles around 0 and 60 degrees giving much wider
versatility than magic angle twisted bilayer graphene. Here we show the
existence of a flat band in the electronic structure of 3{\deg} and 57.5{\deg}
twisted bilayer WSe2 samples using scanning tunneling spectroscopy. Direct
spatial mapping of wavefunctions at the flat band energy have shown that the
flat bands are localized differently for 3{\deg} and 57.5{\deg}, in excellent
agreement with first-principle density functional theory calculations.
