Little-known fact: The largest cathedral in the world is not St. Peter’s in Rome (which is actually not officially a cathedral), it’s St. John the Divine in upper Manhattan. Odder fact: Despite the popish name, it isn’t Catholic, it’s Episcopalian. Oddest fact: Though construction began on the cathedral in 1892, the building is yet to be completed, and many estimate that it will take another 100 years for that to happen.

All of which makes this a fascinating building to visit, as you’ll see a bit of how the ancient cathedrals of Europe might have been built. The 121,000-square-foot structure, a blend of Romanesque and Gothic elements (thanks to the varying tastes of the architects who have worked on it over the past century), is being built without steel, in the classic Gothic manner. To that end, a master stonecutter was brought in from Europe to help train a cadre of American stonecutters in the necessary work in 1979. There’s still much work to be done (including a lot of fundraising!). For over a hundred years a temporary dome has kept parishioners dry; that will eventually be replaced. And an unfortunate fire in one portion of the building has also added to the load of work. But what is in place—and there’s a lot—is quite beautiful, especially the Rose Window in the apse, the largest in North America.

Services here tend to be among the most musical and progressive in the city. I particularly recommend the New Year’s Eve service, featuring original work from some of the best composers in town; and the Blessing of the Animals (on the feast day of St. Francis of Assisi, usually October 4), a ceremony in which New Yorkers bring their pets—ranging from puppies to pythons to thoroughbred horses—to be blessed.

You can explore the cathedral on your own or on the Public Tour, offered Mondays, Wednesdays, Fridays, and Saturdays at 1pm ($18, sometimes also at 11am). Also inquire about the Vertical Tour ($25, Fri and some Sat at 2pm), which takes you on a hike up an 11-flight circular staircase to the top, for spectacular views; and the Triforium Tour ($15, offered Tues, Thurs and Sat at 1pm) which marries a self-guided tour of the ground level with admission to an elevated walkway 5 stories above the cathedral’s floor for a closer look at the building’s architectural features.