Visualisation of a simulated proton-proton collision at 14 TeV centre-of-mass energy resulting in top-antitop quark pair production at the future high-luminosity large hadron collider (HL-LHC). The simulated event includes approximately 200 pileup interactions in the same bunch crossing, and the image shows 88 primary vertices (blue balls) reconstructed along the beam line. From each primary vertex, many different particles are produced, whose tracks are depicted here in light orange. In total, more than 2000 tracks are reconstructed in the proton-proton interaction. The image shows a cutout of the LHC beam pipe at the centre of the ATLAS detector, with a portion of the muon spectrometer and shielding visible in the background. Other parts of the detector have been hidden for a better view of the interaction point.