Greatly anticipated each year is the Serpentine Gallery’s architectural commission for a free-standing structure housed on the grounds directly next to the museum, and this year’s entrant is exceptionally impressive, a gracefully curvaceous “unzipped wall” from Danish architect Bjarke Ingels. Composed of 1,800 hollowed blocks placed in an irregular, jagged step pattern, culminating in a soaring spire at the very top, with beautiful sweeps at the sides, as if the pavilion itself is engaged in the act of respiring, from every angle the building is an ever-changing optic marvel, sometimes breathlessly opaque, sometimes cheerfully, playfully direct. Once inside the crevasse-like entrance, the space opens up expansively, drowned in a soft, translucent light coaxed into the interior by the fibreglass material. The pavilion will be on view until 9 October
Inside the central gallery is a show devoted to the pleasant, if a bit blank, landscapes and portraits of octogenarian American artist Alex Katz. He does have an unmistakable skill with colour, which he wields to great emotional effect, especially in his landscape paintings, suggesting the brilliant, dazzling hue of sunlight on pasture, or the deep, nocturnal play of moonlight on a woodlands. He’s certainly able to engage the senses, and as his work has become steadily more abstract-the suggestive movement of paint on the canvas, meaning held just outside perception- the most recent paintings hold the attention in ways the blunt strokes of his earlier pieces cannot. Alex Katz: Quick Light is on until 11 September
In the newest Serpentine space, the Sackler Gallery (once a storage unit for gunpowder, with two beautiful vaulted chambers) is Etel Adnan’s The Weight of the World, a comprehensive retrospective from this celebrated poet, essayist, artist and feminist, including painting, film, tapestry and poetry. Much of the material addresses dislocation and exile-born in Beirut in 1925, Adnan studied at both the Sorbonne and Harvard, eventually settling in California teaching philosophy. The most interesting pieces in this inclusive overview are her series of vividly coloured suggestions of mountainous landscapes, heavily daubed with paint, replete with the tranquil pain of nostalgia, and her leporello works, accordion sketchbooks of cities with accompanying text, impressive in scale and design detail. This exhibition is also on through 11 September.