The urban centers offered the opportunity for an artisan or small trader to accumulate both status and property. During the eighteenth century, the cost of land in cities and towns rose much faster than the earnings of a typical artisan. One of the first and most important roles of a city is as a place where people can exchange what they have produced or earned for what they need. Colonial cities were the birthplace of political unrest and revolution. The cultural life of the colonies was concentrated in the cities. For almost everyone in the American colonies, whether they lived in cities, towns, or the countryside, social life revolved around two places: the church and the tavern. During the 1760s and 1770s, as the relationship between Great Britain and its North American colonies worsened, the colonies felt growing frustration and economic stress. American cities were hotbeds of many kinds of political thought and activism throughout the colonial period.