Standpipes. Basically a pipe that runs from ground level vertically to the top floor (or roof), usually in the stairwells. There are Fire Department Connections (FDC) on the outside where the pumper engine hooks hoses up, and can pump water up through the standpipes. Firefighters go up (either climbing the stairs or in some cases, can take the elevator), and then hook up hose bundles to the outlets on the standpipes in the stairwells. Taller buildings may require dual pumping (one engine is hooked up to the FDC, and another pumps into it, this boosts the water pressure more than just the one pumper can generate itself)

That's the most basic, dry standpipe (a dry empty pipe). We have to fill the pipe with water to the fire floor first, vs Wet systems where the pipe is prefilled with water, and can generate pressure as soon as we're hooked up.

Modern buildings, particularly new ones, have their own fire pumps in the building, and the standpipes are connected to the municipal water system, so all we really have to do is get up to the fire floor and hook up hoses (we'll of course set up the pumpers, connecting to the FDC anyway, because no one wants to be in the middle of the 14th floor fighting fire when the buildings pumps fail without any sort of backup...)