A few days after the second and final 12-hour installment of Taylor Mac’s Philadelphia performance, a friend emailed a handful of pals who had attended the concert, asking us to contribute to a list of the songs we had seen performed. This was no mean feat, given that Mac and his musicians had delivered more than 200 tunes of this take on American musical history with the underlying theme of “how communities are built as a result of being torn apart.” We had all been awed by the show. Yet in the days and weeks afterward we also shared a keen sense of its slipping away from us, compounded by the startling realization that, in this era of endlessly available documentation, no set list appeared in the program or anywhere on the internet. As of this writing, neither an original cast recording nor any official videos that last more than a few seconds are available. Indeed, surprisingly few audience videos are on YouTube, despite the weary permission (“We know you’re going to do it anyway”) Mac granted us in the opening hour.Two weeks out we were still remembering, reassembling in bits and pieces, the 240 or so numbers—each hour of the performance focused on a decade, and the aim was ten songs for each hour—that made up the core of the performance. Looking back at the emails now, the range of music is staggering. “Can’t believe I forgot about Bowie!” someone wrote in response to a note recalling “Heroes.” “Amazing Grace?” one person queried. “Yes! Plus ‘Turkey in the Straw” and “Take Me Out to the Ballgame,” came another’s response. We also tried to catalog the numerous moments of audience participation, where Mac asked the audience to reenact history. We had hurled ping pong balls at each other to reenact the Civil War. We had slow-danced with strangers of the same sex while Mac talked about the jukebox at the Stonewall Inn. Wearing blindfolds, we had caressed each other’s faces, as well as those of strangers, with grapes (I’ve forgotten which historical event this was intended to portray). At various points in the performance, some of us had been brought up on stage because we could swing dance, some because we were lesbians, some because we were men under forty and would have been drafted to fight in WWI, and some because, for the 1840s, Mac needed a stage lined with prone bodies playing Stephen Foster in a coma.Unsurprisingly, the “did-that-really-happen” feeling pervading this exchange has more than a little to do with the sheer awe inspired the performer. Mac—whose pronoun of choice is the gloriously awkward judy—possesses a tenor that can soar regally and probe tenderly. Judy’s voice did not show significant signs of strain until the last hour of the second installment, when Mac sat at the piano in briefs, singing a few original songs. Judy moved constantly— whether taking part in choreographed dance numbers, or walking through the aisles and rows (usually muttering, “Move your shit, move your shit”) to interact with individual audience members, or sliding down a pole, and so on. There was a little rest when the stage was taken over by a head-spinning series of guest appearances: Urban Bush Women, Toshi Reagon, performance artist Martha Graham Cracker, a local queer trapeze group, and a youth drum corps from across the river in Camden.The result was that the piece became ephemeral through a surfeit of content. Macarthur Fellow Mac delivered each decade’s playlist while focused on some historical phenomenon: indigenous genocide, abolition, Reconstruction, women’s suffrage, the Great Depression, gay liberation, and so on. Throughout, Mac appeared in a stunning array of non- (or at least not-obviously) thematic costumes, reaching from the top of the headgear way above judy’s head to the very bottom of judy’s spiked heel, bold bursts of extravagant costumes featuring spiraling feathers, complicated layers and webs of fabric, and kaleidoscopic colors. Combined with a base of white face makeup, the effect was a mélange of drag queen, kabuki singer, Medusa, and 3-d Pollock painting. Yes, this was the figure who kicked off the 24 hours of show with a 1770s song complaining crankily about the Continental Congress.While beginning with the origins of the nation, Mac used the songs to tell stories about America that refused to cohere as nostalgia or nationalism. With an early performance of “Yankee Doodle Dandy,” judy introduced a recurring theme: the cultural “fear of effeminate men” and the eventual “revenge of the dandy.” (Mac framed the song as British North American colonists’ appropriation of the fag-baiting to which they were subject by British commentators back home; perhaps drawing on the work of historian Henry Abelove). Queer politics and queer performance traditions certainly provide a foundation for the show, but in truth judy seemed less interested in identifying a specific “alternative” history than in exposing and playing with audiences’ implication in the power dynamics and erasures through which popular song takes shape and is transmitted.At one point, for example, Mac and orchestra performed a rousing ditty called “Coal Black Rose,” a merry song full of what seemed like bawdy drinking-song clichés, until judy broke off the song in medias res to scold the largely white audience, “Why are you laughing? That song is about a group of white men getting to rape a black woman slave!” In isolation this would be a rather cheap, staged gesture of calling out—only a handful of scholars might have known the song’s origins—but the performance in toto provided a context so that the moment stood in for the many acts of forgetting that take place as songs move through history. Here, the point was that this process masks violence in the name of perpetuating the (white) enjoyment that, in another time and space, could be more openly grounded in racism and sexual exploitation. Other times, though, Mac illustrated the seething articulations of righteous rage such flexibility can make available, perhaps most stridently in judy’s balls-to-the-wall queer rendition of Ted Nugent’s “Snakeskin Cowboys.”One decade in the show felt like something of a centerpiece. In the segment dedicated to the 1840s, Mac staged an audience-judged competition to determine the rightful bearer of the title “father of American song”—should it be Foster, the traditional choice, or Walt Whitman, the opera-queen author of the queerest text in the already wondrously bent American literary canon, “Song of Myself.” Our father Foster, Mac told us, was a professed abolitionist, but he also wrote songs steeped in blackface minstrelsy (“Camptown Races”) and romanticizing relationships between the enslaved and their owners (“Massa’s in the De Cold Ground”). Judy juxtaposed these awful numbers with spirited recitations of passages from “Song of Myself,” after which the audience was asked to vote by yelling either “O Captain, My Captain” or “Doodah, Doodah.” In front of a majority-white-liberal audience, this seemed like a fixed match, with Whitman set up to win each round handily. But then Mac sang a gorgeous version of Foster’s achingly delicate ode of class struggle, “Hard Times Come Again No More” and a big chunk of the audience, myself included, found itself ceding him a round. It was a reminder to avoid getting too comfortable with our feelings as listeners; pop is nothing if not impure, a quality that might in itself seem worthy of celebration, if it weren’t for the inevitable ass-bitings it continually administers.With this segment, Mac also made the anti-slavery movement the foundational moment for a running critique of white liberalism (which extended into a back-and-forth with defensive audience members who shouted “But Philly is different!” when judy mentioned, somewhat goadingly, that it was always strange performing in red states). The performative apex of this thread came in the second half, during the 1950s, when Mac asked all the white members of the audience sitting in the center sections of the theater to move to the sides, and all the people of color in the audience to move to the center, a set-up meant to embody white flight to the suburbs. One of the performance’s most provocative moments came at the end of this segment, when Mac requested that white audience members who’d been displaced not ask for their seats back, a direct confrontation of the tense relation between cultural consumerism and activism that, apparently, doesn’t always go off as hitchless as it did here.In this time of music streaming services and the always-available pop archive, Mac’s maximalism might seem symptomatic, a bit like Spotify brought to life. On the contrary, though, what makes the piece so engaging, if melancholic, is its very ephemerality. It evades preservation, whether on the internet or in memories addled by it, because it is, simply, too much to grasp. I brought a notebook to the first show and never pulled it out. I took video of a couple of segments; onscreen, they look impossibly small and quiet. Anyway, no one song can provide anything akin to the feeling of the piece; on site, whipping out the phone just seemed futile and distracting. Mac is now performing two- and four-hour segments and condensations of the show—judy announced from the stage that these 12-hour Philly shows would be the final “durational” performances—and it seems clear that the nature of these performances would be wholly different.We’re often told that people today prize vinyl and slow fermentation because they’re starved for materiality in a post-analog world, but in 24-Decade History, the cure for that ill seems to be more and better immateriality. It seems to be the creation of situations that evade social media and cellphone video, like a white liberal’s internal drama about whether to ask for that $200 seat back, or the surprisingly healing feel of a stranger’s grape caress. It is, quite simply, a masterpiece, and this sublime juxtaposition of the massive and the fleeting is in large part why.