  Proxima Centauri has become the subject of intense study since the
radial-velocity discovery by Anglada-Escud\'e et al. 2016 of a planet orbiting
this nearby M-dwarf every ~ 11.2 days. If Proxima Centauri b transits its host
star, independent confirmation of its existence is possible, and its mass and
radius can be measured in units of the stellar host mass and radius. To date,
there have been three independent claims of possible transit-like event
detections in light curve observations obtained by the MOST satellite (in
2014-15), the BSST telescope in Antarctica (in 2016), and the Las Campanas
Observatory (in 2016). The claimed possible detections are tentative, due in
part to the variability intrinsic to the host star, and in the case of the
ground-based observations, also due to the limited duration of the light curve
observations. Here, we present preliminary results from an extensive
photometric monitoring campaign of Proxima Centauri, using telescopes around
the globe and spanning from 2006 to 2017, comprising a total of 329
observations. Considering our data that coincide directly and/or phased with
the previously published tentative transit detections, we are unable to
independently verify those claims. We do, however, verify the previously
reported ubiquitous and complex variability of the host star. We discuss
possible interpretations of the data in light of the previous claims, and we
discuss future analyses of these data that could more definitively verify or
refute the presence of transits associated with the radial-velocity discovered
planet.
