Peter Berger describes some of his own experiences seeing religiosity break into city life and sums up with these thoughts:
Years later I took a course at the New School of Social Research under Albert Salomon entitled “Balzac as a Sociologist”. I sensed that Balzac’s novels conveyed the same experience of Paris, all its secrets hidden behind closed doors. What could be going on behind this particular door: a religious cult (Balzac was curious about esoteric cults), a great crime, an orgy, or a political conspiracy? During my student days I roamed endlessly through New York; since I was already obsessed with religion (as a friend of mine once put it, rather pejoratively, “once a godder, always a godder”), I visited every sort of religious space—not only regular Christian churches and different synagogues, but any manner of what for me were esoterica: a brand-new Zen center, the Anthroposophical Society and its cultic offspring, the so-called Christian Community (where one could attend a quasi-Gnostic ceremony in 20th-century America), a Mormon church, Pentecostal storefronts in Puerto Rican East Harlem (about which I wrote my M.A. thesis, my hands “dirty with research”), and the Baha’i (about which faith I wrote my doctoral dissertation). I could go on. But enough. I will observe that mystery is always, minimally, akin to the core of religious experience which Rudolf Otto (in my opinion the greatest 20th-century scholar of religion) called the mysterium tremendum. Thus it should not be a surprise that cities have typically been places of religious innovation (Pentecostalism, the biggest religious explosion of our time, mainly flourishes in the intensely pluralistic mega-cities of the Global South).
While cities are often regarded as centers of secularization and financial markets, they often contain a remarkable amount of religious activity. Two books I have read recently attest to this. In How the Other Half Worships, sociologist and photographer Camilo José Vergara looks at a number of urban churches primarily through images with some explanation of the experiences had within the diverse church buildings. While Vergara roams far and wide in poorer neighborhoods, sociologist Katie Day examines the dozens of religious congregations along Germantown Avenue in Philadelphia in Faith on the Avenue: Religion on a City Street. Both books hint at the lively religious life of urban residents and organizations even as other aspects of cities receive much more attention from scholars.