Between the first decades of the nineteenth century and the dawn of the twentieth, the numbers of US Catholics grew from 200,000 to more than 14 million. This growth was made possible by an increasing birth rate but also successive waves of immigration, predominantly from Europe. During this era, US Catholics developed a dense network of imposing and influential institutions: cathedrals (some of surpassing architectural elegance), parish churches, and various types of schools, orphanages, hospitals, convents, monasteries, and seminaries. Even in places where Catholics were a minority or whose Catholic populations grew slowly, Catholic enclaves often flourished.