The largest Roman Catholic cathedral in the United States, St. Pat’s is also the seat of the Archdiocese of New York. Designed by James Renwick, begun in 1859, and consecrated in 1879, St. Patrick’s wasn’t completed until 1906. The vast cathedral seats a congregation of 2,200; if you don’t want to attend Mass, pop in between services to get a look at the impressive interior. The St. Michael and St. Louis altar came from Tiffany & Co. A self-guided audio tour, available on the website for $25, provides an erudite introduction to the cathedral’s history and architecture, narrated by Cardinal Timothy Dolan. We also highly recommend visiting the original St. Patrick’s Cathedral down in SoHo for a tour of its catacombs.