Moments of unexpected magic are the Newport Folk Festival's calling card. The festival typically sells out well before its lineup is even announced — but the official lineup is more of a rough guideline, anyway, since the weekend is peppered every year with surprise performances and collaborations.

An unannounced slot at the smallest of Newport's main stages turned out to belong to Nathaniel Rateliff and The Night Sweats, who played some new music with the Preservation Hall Jazz Band and finished out their set by parading, second-line style, through the enormous crowd that had assembled.

Hiss Golden Messenger's M.C. Taylor assembled a few friends — including Justin Vernon, Phil Cook and Natalie Prass — to perform a tribute to Bill Withers' music.

And master songwriter John Prine, who played Sunday evening's last set, brought out Vernon, Rateliff, Jim James, Margo Price and Roger Waters, before a stageful of the weekend's performers gathered to sing "Paradise."

Newport's most dedicated festivalgoers, affectionately known as the Folk, know to expect surprises like this; they're what have made Newport Folk Festival one of the country's most unique and beloved music festivals for almost 60 years.

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