The cover of this issue illustrates how a scanning tunnelling microscope can be used to create complex electronic and spin artificial lattices atom-by-atom; in this case fractal structures known as Sierpiński gaskets. See Alexander Khajetoorians et al.

The cover of this issue illustrates the fluid dynamics of insect flight as part of the focus celebrating George Gabriel Stokes’ multidisciplinary legacy. See Itai Cohen et al.

The cover of this issue shows a series of snapshots from a numerical relativity simulation of two merging neutron stars. See Huerta et al. and Mészáros et al.

The cover image this month is a colour 3D X-ray image of a fatty deposit on an artery (carotid plaque) taken using a Medipix detector. See Feature.

The cover of this issue shows the Beijing Spectrometer III (BES III) detector at the Beijing Electron–Positron Collider II. See Changzheng Yuan & Stephen Olsen.

The cover of this issue illustrates the idea that the Large Synoptic Survey Telescope could uncover the relationship between dark matter and galaxies. The image shows a density projection of a cosmological simulation, transitioning from the entire dark matter distribution to the densest regions of dark matter halos corresponding to galaxies. See Robertson et al.

The cover of this issue shows a photograph of a spontaneous parametric down-conversion Type I beam and is inspired by a Review on imaging with quantum states of light. See Moreau et al.

The cover of this issue represents the Hofstadter butterfly and is inspired from a Perspective on topological quantum matter in synthetic dimensions. See Ozawa & Price

The cover of this issue shows the Large Hadron Collider at CERN. In a Focus on future particle accelerators we explore the proposed projects and underlying technologies that would make the next big particle collider possible. See Editorial

The cover of this issue is from a Review surveying 3D metamaterials with unprecedented physical properties in electromagnetism/optics, acoustics/mechanics and in transport, made possible by advances in design and manufacturing. See Kadic et al.

The cover of this issue is from a review of the new physics that emerges in van der Waals heterostructures consisting of graphene and hexagonal boron nitride, including the integer and fractional quantum Hall effects, new plasmonic states and the effects of emergent moiré superlattices. See Yankowitz et al.

Image: Subramanian P. Ramanathan, Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, Missouri 64110, USA. Design: Carl Conway, inspired by the Review on p41.