A monument has touched down on the Metropolitan Museum’s rooftop that a few decades ago I would never have dreamed of finding there: an architectural mothership packed with a cargo of ideas and images encompassing eons of Black American life.

The latest and one of the best in the Met’s 10-year series of annual Roof Garden commissions, the monument was designed by the young California artist Lauren Halsey. In conceiving it, she has evoked ancient forms found in the Met’s Egyptian collection. She has conjured up the Pharaonic funk and empyreal jazz of George Clinton and Sun Ra. And she has streamed in, hot from the street, the urban culture of the South Central Los Angeles neighborhood where she grew up and where she still lives.

Finally, she has encapsulated all this richness in a 22-foot-high architectural cube, creating a kind space station/sanctuary, open to the sky and to spectacular views of the city and Central Park.

A direct inspiration for the structure would appear to be the museum’s famed Temple of Dendur, here reshaped and reduced in size, flanked by four sculptural sphinxes and free-standing columns, its walls covered inside and out with low-relief words and images. But the comparison with an ancient Egyptian model only goes so far.

Much of the actual content in Halsey’s version is contemporary and personal. The faces of the sphinxes are all portraits of members of her family: her mother, Glenda, her cousin Aujane, her brother Dominic, her life partner, Monique McWilliams. The same with the columns. They’re all based on a single fourth-century example on view in the Met’s galleries. But Halsey has replaced the images of the Egyptian goddess Hathor on the original with likenesses of South Central artist-friends.

The wall inscriptions, hand-incised or cut in low relief, are, for the most part, local and personal too. Where the ancient Egyptians covered the walls of their tombs and shrines with illustrations from the Book of the Dead, Halsey and her team of artists and artisans have created an immersive Book of Everyday Life, one focused on, but by no means restricted to, contemporary Black urban existence, evoked and preserved in words and images carved into hundreds of concrete panels.

Halsey, who is 35, has described herself in interviews as a born archivist, committed from the start to collecting and preserving traces of Black popular culture, past and present, following an example set by her history-minded father. After high school she went to a local community college to study architecture, learned Photoshop there, and put her information-gathering, not to say hoarding, impulses to work in minutely detailed digital collages.

She continued to produce these, on an ever-expanding scale, as an undergraduate at California College of the Arts. Then, after entering the MFA program at Yale in 2013, she moved in a 3-D direction. During a subsequent residency at the Studio Museum in Harlem, she began carving words and images on gypsum panels, creating a beta version of her first full-scale environment, “The Crenshaw District Hieroglyph Project (Prototype Architecture),” which would appear in the 2018 biennial exhibition “Made in L.A.” at the Hammer Museum and attract wide attention.

It was with that remarkable piece that the full social and political, as well as the anthropological, intentions of her art became clear. Within a museum context, her walk-in enclosure of panels carved with words and images harvested from daily life in the Crenshaw section of South Central made the piece a valuable repository of cultural history, but a frozen one. Halsey’s goal, in fact, was to reconstruct the piece in public, in the neighborhood itself, making it an accessible and interactive community resource and gathering place where anyone could extend and update a collective history by inscribing their own on the walls.

For a while it looked like her intentions might be realized. A Kickstarter campaign she launched was a success; the Hammer gave her a best-of-show cash award. Then COVID-19 hit and Halsey put all her time and resources into a collaborative public service effort she called “Summaeverythang,” which provided South Central residents with, among other things, free food in a very bad time.

Her Met piece is basically an extension, variation and elaboration of the Hammer project, as its title (all in lowercase) suggests: “the eastside of south central los angeles hieroglyph prototype architecture (I).” Again — as always — community is both the source and the subject of Halsey’s art, and references to it spread over the more than 700 engraved and sculpted panels that make up the Roof Garden installation.

Versions of actual present or past commercial signage, much of it advertising Black-owned businesses, recur (Akkeli Black Man Car Wash, The Braid Shack, Vanessa’s Positive Energy), as do names of grass roots civic organizations (Community Youth Center Chill House, Sons of Watts Community Patrol). Terse placard-style statements of protest (Still No Justice, Reparations Now) alternate with lift-up existential exhortations (Keep the Future Alive, Go for Your Funk, Be Who You Is, Together We Can).

All of these phrases, in eye-grabbing typefaces and graffiti fonts, intertwine and overlap with images related to fashion, hair styling, nail-styling, churchgoing and utopian architecture, including Italy’s Superstudio. References to the liberatory, Black-positive, space-is-the-place movement known as Afrofuturism (flying saucers, floating pyramids, superhero figures, religious symbols, Parliament-Funkadelic props) are prominent in the mix. So are images of items from the Met’s collection that caught Halsey’s eye during her New York research forays over the past two years. (Her commission was originally scheduled to go up in 2022; Covid-related issues delayed it.)

These range from Old Kingdom busts to decorative passages she found on tomb frescos, to a diagrammatic map of Seneca Village, the early-19th-century mostly Black settlement that was originally located a short walk from where the Met is now but was leveled to make way for what became Central Park. (The same map appears on a wallcovering designed by the artist Njideka Akunyili Crosby for the museum’s ongoing 2021 installation “Before Yesterday We Could Fly: An Afrofuturist Period Room.”)

Unsurprisingly, given Halsey’s activist practice and rooted loyalties, the Met’s roof garden is functioning both as a landing pad and as a launchpad for her commission. In October, when its Met run is done, the installation will be disassembled, packed up, and sent to what might be called its spiritual home: South Central Los Angeles.

The plan is to have it reconstructed there in a public space to be — what? A community center that’s also a civic monument, that’s also a collaborative work of art, that’s also a history book of a neighborhood that Halsey has seen vanishing before her eyes under the relentless tide of disenfranchisement and gentrification.

It’s the same tide that wiped out Seneca Village and that continues to batter and scatter Black and Brown Americans coast to coast. So in this sense the Met commission — organized by the artist in consultation with Sheena Wagstaff, former chair of modern and contemporary art at the Met, and Abraham Thomas, its present curator of modern architecture, design and decorative arts — is very much a New York piece too.

And it feels that way, up there on high, with “Cleopatra’s Needle,” the monumental, 3,000-year-old, Met-owned Egyptian obelisk rising to a point in the park below, and pyramids of all shapes and sizes topping Manhattan buildings everywhere you look, in a city of vivacious, ever under-threat Black and Brown neighborhoods, precious, present and gone.

The Met Roof Garden Commission: Lauren Halsey

Opens to the public April 18 through Oct. 22, Metropolitan Museum of Art, 1000 Fifth Ave., (212) 535-7710; metmuseum.org.