Concrete caves and extravagant butterflies in the American Museum of Natural History’s extension

“You gotta see this.” Architect Jeanne Gang pulls me towards a corner of her new half-a-billion-bucks entrance and extension to New York’s American Museum of Natural History. There she bends down to peer not at an architectural detail but at an installation: a procession of leafcutter ants marching relentlessly up and down columns, along bridges, through mazes, in a tube over the ceiling and down into a bank of glass bottles in which they have created their knobbly fungal-spongy homes. “This,” she says, mesmerised, “is, like, my favourite exhibit ever.”

Before her new bit of the building was slotted in, the museum was a little like the assault course devised by the entomologists for those ants: a challenging series of dead ends, dingy connecting links populated by dusty vitrines and odd corridors. A few hours before the extension opened, I got lost at Molluscs of New York and had to walk through the African megafauna dioramas three times to find the Plains Indians who were placed, disconcertingly, beside the primates. Now it feels as if everything is connected, which is precisely the point of the museum.

The architecture of the new Richard Gilder Center for Science, Education and Innovation is a surprise. The museum’s last major extension was the Death-Star-in-a-glass-box Rose Center for Earth and Space. This is something very different: the opposite of high-tech, it looks deliberately simplistic, cavelike. Chicago-based Gang, whose work includes the seductively liquid Aqua Tower in Chicago and the just-opened Arkansas Museum of Fine Arts in Little Rock, is not much interested in theoretical justifications or a big spiel about what it all means. Instead she talks about how “cool” it was to get a building on an axis (with 79th Street) so you get the “Manhattanhenge” effect where, twice a year, the sun shines straight down the street and into the atrium.

If some museums can be hard to find your way into, this new entrance is unmissable. Opening off a small landscaped public park, the atrium sits between two inclined cliffs, clad in the same pink granite used on the museum’s massive Central Park West entrance. Inside, it gets more rustic: instead of finished stone, the material is rough, gnarly concrete.

The material is called shotcrete, which is sprayed rather than poured or cast, a projectile vomit of knobbly cement applied to reinforcement bars which becomes both structure and surface. Its use highlights a fascinating historical link to this particular place as it was invented by Carl Akeley (1864-1926), who also became influential for his animal-stuffing methods at the museum and was responsible for many of its most memorable, if surreal, dioramas (as featured coming to life in the film series Night at the Museum).

It’s a fascinating material which imparts that elemental, cavernous feel but it is also problematic. To revel in concrete in this way in a museum dedicated to a message of saving species looks insensitive to say the least. Concrete is notoriously carbon-intensive in its production and its celebration here raises questions. Gang attempts to answer them by suggesting that “real sustainability is a building that lasts” — but who can tell if anything will last? This is a rough finish, and friable. Kids will inevitably be picking at it and scratching into it. More widely used in the construction of tunnels, pools and landscape retaining walls, its adoption in such a public space is unusual.

Whatever its implications, the shotcrete defines the interior and this Swiss cheese of a building, with its arches, holes, caverns and routes, is undeniably dramatic. The openings make for legible connections, the very thing this museum, accreted over the century, so obviously lacked. Its structure allows visitors to see deeper into the institution and understand where they are going. At its centre is the now obligatory atrium/stair/auditorium for events and gathering — one of the weaker points, the straight edges of the stairs contrasting with the fluid lines of the structure, undermining its organic form. It might have been better to create a more flowing stair, a laval form to maintain the notion of this as a topography rather than an architectural interior, as Zaha Hadid might have done.

Given her ant fascination, I wondered if insect nests — lumpy, creamy, a little chaotic, hard but brittle, something between geology and biology — inspired the look Gang was trying to achieve in the new atrium and entrance hall. But no. We are looking at spaces which, she suggests, appear “as if they had been eroded away by water, wind and time . . . where canyons had been created”.

Modern museums, with their move away from the artefact and towards a more experiential storytelling mode, are beginning to converge with the theme park. In fact the apex of this extension is, arguably, the Vivarium, a celebration of life rather than taxidermied afterlives or fossils. A brilliantly lit hothouse of a room in which the most extravagantly gorgeous butterflies flap silently around you as you wander through lush tropical vegetation: it is a celebration of beauty. With windows on to the city streets, it brings exotic life into the heart of the institution. And because they are insects, like the hard-working leafcutters, presumably no one bothers too much about their emotions or how they feel about being here.

Despite its $465mn price tag, this is not an enormous new building but a work of great complexity which stitches together an existing ecosystem of buildings and landscapes and does it extremely well. On one side it gives glimpses of an on-site archive of 4mn objects through a huge glass vitrine of intriguing artefacts. On another it creates a dazzling new entrance and connection to the city grid, while all around it opens up routes, passages and flows. It has added extensive education spaces, a glorious library with a mushroom-shaped ceiling, a café and spaces for interpretation and study.

It might last, it might be fantastically sustainable. But then again, like so many of the species, peoples and cultures on display, it might not. This is the scenography of climate crisis, as entangled and problematic as its subject, both about, and part of the problem. And the problem, of course, is us.

amnh.org