A year ago, I perpetrated an online piece entitled "A Walking Tour of Wagner's New York," tracing a curious itinerary in a city that Wagner himself never saw. I hadn't imagined anyone following in my eccentric footsteps, but Amelia Lester, the editor of the Goings On About Town section of the magazine, had the idea of concocting a walkable tour, as part of a series of New York audio guides that can be found on the Goings On smartphone and tablet app. Eventually, we came up with an excursion called Musical Mysteries of the Upper West Side, embracing not only the Parsifal bells of Riverside Church and the vaguely Wagnerian ambience of the Cathedral of St. John the Divine but also the mysterious world of Nicholas Roerich, noted for his affiliations with figures as various as Stravinsky and Henry Wallace. The tour begins at the Roerich cornerstone, at West 103rd and Riverside Drive, and ends at Riverside Church, where, alas, Frederick C. Mayer's Parsifal sequence is still being played in the wrong order. I hope it makes for a diverting couple of hours. Many thanks to Owen Agnew for crafting a narrative from my slightly demented ramblings.