  Aharonov-Bohm (AB) effect, the well-known archetype of electron-wave
interference phenomena, has been explored extensively through transport
measurements. However, these techniques lack spatial resolution that would be
indispensable for studying the magnetic and electrostatic AB oscillations at
the nanometer scale. Here, we demonstrated that scanning tunneling microscopy
(STM) can be used as an AB interferometer operating on nanometer length scales
and the magneto-electric Aharonov-Bohm effect in minimally twisted bilayer
graphene (TBG) was directly measured by using STM. In the minimally TBG, there
is a triangular network of chiral one-dimensional states hosted by domain
boundaries due to structural reconstruction. Taking advantage of the high
spatial resolution of the STM, both the magnetic and electrostatic AB
oscillations arising from electron interference along moir\'e-scale triangular
quantum paths in the minimally TBG were measured. Our work enables measure and
control of the AB effect and other electron-wave interference at the nanoscale.
