Why are there spikes on top of buildings?

There are three general items we place as poles or spikes on top of buildings.

First, lighting rods. I only use this first as they’ve been around the longest. Lighting has a huge amount of amps and volts, so we give a convenient path for that power rather than through sensitive electrical systems like you and your computer.

Second, antennas. Radio, cell phones, whatever needs and antenna. Heres a large vertical object that can see further over the horizon than from below so it’s a convenient spot to place them.

Last, aviation lights. Since skyscrapers tend to be rather tall compared to surrounding objects we place warning lights on them so planes are more likely to see them and go around, over or generally miss the building altogether.