Classic example of subterranean termite mud tubes. The "mud" is used to make a protective cover over their feed and travel tunnels.
Carpenter Ant damage can look like termite. It takes an experienced pro to know the difference
This is an example where the structure is all cinderblock. These tubes are built inside the block as well as the exterior. The termites have made their way all the way to the ceiling and roof line. Where there is plenty of wood to feed off of.