  Quantum mechanics is strictly incompatible with local realism. It has been
shown by Bell and others that it is possible, in principle, to experimentally
differentiate between local realism and quantum mechanics. Numerous experiments
have attempted to falsify local realism; however, they have consistently failed
to close the detection loophole under strict locality conditions, thereby
allowing local realistic explanations for their observations. In 2015, three
experiments took place that tested local realism without the impediments of
these significant loopholes. Between these three experiments, a substantial
data set was collected. All of the collected data show a strong violation of
local realism and strong support for quantum mechanics. This article reviews
the theoretical basis of Bell tests and the affiliated loopholes, as well as
the methods employed by these recent experiments and the implications of the
results they observed.
