The ARoS Aarhus Art Museum in eastern Denmark, home to Olafur Eliasson’s rainbow rooftop walkway, is embarking on a dramatic $34m underground expansion. James Turrell is creating an immersive light installation called the Sphere that visitors will pass through on their way to a new gallery. A second space dedicated to performance art will be topped by the US artist’s Pantheon-inspired Dome, which offers a view of the sky through a circular hole in the ceiling. The 1,200 sq. m expansion is funded in part by the Dansk supermarket’s Salling Fondene charity, which donated $14.9m.