 Complete the following phrase:  Although barricade construction began in France in the sixteenth century and remained an exclusively French practice for two centuries, the nineteenth century remained the classic era of the barricade. Contrary to a number of historical sources, barricades were present in various incidents of the great French Revolution of 1789, but they never played a central role in those events. They were, however, a highly visible and consequential element in many of the insurrections that occurred in France throughout the 1800s, including in the revolutions of 1830 the July Days and 1848 in both February and June. Other Parisian events included the 