“This is the biggest infrastructure project after the interstate highway system,” says Sean Shahini, CEO of Inorsa, an engineering startup that focuses on lean, fast 5G network site builds. Those sites aren’t just retrofits of existing 4G towers: Some will proceed easily, but “the range of (most of) our antennas is way less than with 4G, so instead of building 100 antennas, for example, to cover Manhattan, we have to build 5,000 to 20,000 antennas,” says Shahini.