We were invited by the EIC of Europhys. Lett. for a Perspective paper on higher-order topological insulators. We wrote on the relation between Dirac cones and higher-order topological phases in quasi-continuous media (i.e., photonic and acoustic crystals). The paper entitled with "Dirac cones and higher-order topology in quasi-continuous media" (https://arxiv.org/abs/2112.00352) is going to appear on Europhys. Lett. soon (Europhys. Lett. 137 (2022) 15001).