 The incompatibility of theories satisfying the conditions that entail Bell inequalities with the predictions of quantum mechanics permits an experimental adjudication between the class of theories satisfying those conditions and the class, which includes quantum mechanics, of theories that violate those conditions. At the time that Bell formulated his theorem, it was an open question whether, under the circumstances considered, the Bell inequality-violating correlations predicted by quantum mechanics were realized in nature. Beginning in the 1970s, there has been a series of experiments of increasing sophistication to test whether the Bell inequalities are satisfied. With few exceptions, the results of these experiments have confirmed the quantum mechanical predictions, violating the relevant Bell Inequalities. Until recently, however, each of these experiments was vulnerable to at least one of two loopholes, referred to as the communication, or locality loophole, and the detection loophole (see section 5). Finally, in 2015, experiments were performed that demonstrated violation of Bell inequalities with these loopholes blocked. This has consequences for our physical worldview; the conditions that entail Bell inequalities are, arguably, an integral part of the physical worldview that was accepted prior to the advent of quantum mechanics. If one accepts the lessons of the experimental results, then some one or other of these conditions must be rejected.