There’s never a shortage of mega-art in Chelsea: a stroll one morning this week encountered such gallery-filling works as Jordan Wolfson’s deranged, chain-operated marionette (“Colored sculpture,” 2016) at David Zwirner and Anish Kapoor’s mammoth, packed-earth “She Wolf” (2016) at Gladstone. And then there’s Richard Serra, whose double-gallery blowout at Gagosian is Exhibit A for material-intensity-meets-overwhelming-scale. There’s nothing else like it.

With this show, or rather, shows — the two venues are separately titled with the names of the sculptures they contain, NJ-1 and Above Below Betwixt Between, Every Which Way, Silence (for John Cage), Through — Serra is following the same playbook as his previous two-gallery presentation at Gagosian, which was held from October 26, 2013, to March 15, 2014: a walk-through sculpture on 21st Street and three others composed of enormous slabs of steel, standing and at rest, on 24th.

And yet he manages to surprise, even shock. The walk-through on 21st, “NJ-1” (2015), dispenses with the familiar torqued walls that made up “Inside Out” (2013), his previous work in the same space. Instead, his rusted sheets of weatherproof steel, more than 13 feet high, make up a doubled oblong shape that lists to one side like a sinking oil tanker.

You enter at one end between two sets of walls, as if you’re walking down the center aisle of a chapel. When you reach the end, you can turn right or left, but either way will take you through a series of compressed and expanding spaces, a path that is simultaneously terrifying (depending on your tolerance for tight enclosures) and exhilarating.

It’s hard to avoid the deeply unsettling sensation of standing beneath a very tall, very heavy wall that’s literally leaning over your head. But the purity of Serra’s forms and the spaces they carve out, both in the passageways and in the apertures admitting light from above, are dazzling in the distilled beauty of their stark geometry. This is art that’s stripped to the essentials yet doesn’t shy away from spectacle — a paradox, but not a facile one. It trusts its forms first, and the emotional response of the viewer follows from that.

This is especially true of the works on 24th Street. The sculptures don’t swallow you up; they are works you walk around, not through, which engenders a more conventional art/viewer relationship. But that doesn’t mean you’re off the hook. Looking at these massive objects, it’s easy to feel unnerved, if not threatened, especially when coming upon the tonnage of “Silence (for John Cage)” (2015), a 16-inch-thick slab of forged steel, nine feet across and nearly 30 feet long, lying flat on the floor. The sheer density of the thing can leave you speechless, though that isn’t the kind of silence Cage had in mind: Cage’s silence was meant to foster acute listening, so that everything audible would become music; Serra’s “Silence” exerts such downward pressure on the space around it that you ignore everything, including sound, that might interfere with your absorption in its frightening mass.

In the gallery’s largest room, “Every Which Way” (2015), a piece composed of 16 slabs of waterproof steel, the tallest being 11 feet high, is an echo of “Intervals” (2013) from the previous show. While the walls comprising the latter work were fairly uniform in height, none taller than six feet, in “Every Which Way” they go from just over your head to way over your head. The earlier sculpture had a funereal air about it, as if the slabs were tombstones, and brought to mind Peter Eisenman’s Holocaust memorial in Berlin. Here, the taller walls seem to rise in the herky-jerky rhythms of the city’s skyline, evoking the New York paintings of Piet Mondrian as well as the Metaphysical street scenes of Giorgio de Chirico.

The large gallery displaying “Every Which Way” is still imprinted, in my mind at least, with the memory of “7 Plates, 6 Angles” (2013) from the earlier show, which featured horizontal slabs eight inches thick by eight feet tall by 40 feet long. It dominated the space with a brute force that is unimaginable in a work of lesser magnitude. “Every Which Way” seems to have made a virtue out of its differences with that masterstroke of art and engineering, coming on lightly with a clarity of space and scale: the black slabs stand in a stately progression, cutting deeply into the visual field presented by the room’s white walls, with the gaps in between feeling as crisp as Alpine air.

The third sculpture on 24th Street, “Through” (2015), is composed of three large steel slabs forming horizontal walls, two together, one apart. This piece and the the room-sized black oilstick drawing, “Above Below Betwixt Between” (2016), also make impressive use of their impressive scale (with “Through” providing an ample helping of Serra’s sumptuous, painterly surfaces), though it’s hard to top the works in the two adjoining rooms.

At this point, however, it is worth noting the enduring, obdurate simplicity of Serra’s practice. Compared to his comrade-in-arms, Frank Stella, who went back to basics as radically as Serra did, and then proceeded to run off the Minimalist rails with ever-rising mountains of impossibly complex paintings and sculptures, Serra has hardly varied from his elementary tools of metal (primarily lead and steel) and black oilstick. That he has investigated the possibilities of these two mediums decade after decade (he is now 77 years old) is astonishing in itself, let alone the powerhouse revelations he has been able to wring from them.

Moving from one room to another at the 24th Street location brought a palpable feeling of anticipatory excitement — a rare sensation in contemporary art. Serra is like a movie director who can generate suspense even if you know the ending. The next piece will be big, to be sure, and it will be steel. Otherwise, it’s anybody’s guess.

Stella’s vision has plunged irretrievably into the Baroque, and his tangles of pattern, line, color, and shape can be as mind-bending as they are exhausting, like an exegesis from a brilliant speaker who doesn’t know when to shut up. Serra’s blunt, taciturn statements started off as clear, refined, and straightforward, and despite the twists and turns of his torqued ellipses, they have remained that way, resting on geometric certitudes, a Classicism that is as timeless as it is dark, dense, and earthbound.

Richard Serra: NJ-1 is on view at Gagosian Gallery (522 West 21st Street, Chelsea, Manhattan), and Richard Serra: Above Below Betwixt Between, Every Which Way, Silence (for John Cage), Through is on view at Gagosian Gallery (555 West 24th Street). Both exhibitions run through July 29.