Air inside: A scanning electron microscope image of the hollow-core fibre. (Courtesy: Petrovich, M, Numkam Fokoua, E, Chen, Y et al. "Broadband optical fibre with an attenuation lower than 0.1 decibel per kilometre" Nat. Photon. 2025 https://doi.org/10.1038/s41566-025-01747-5) Optical fibres form the backbone of the Internet, carrying light signals across the globe. But some light is always lost as it travels, becoming attenuated by about 0.14 decibels per kilometre even in the best fibres. That...