Carpenter ants build their nests in hollow, dead and decaying wood, and termites make dirt tunnels that would reach all of the way to the ground.  A type of wasp called a mud dauber will build a tunnel nest to lay its eggs in. Wasps usually evoke a great deal of anxiety or fear. However, solitary wasps such a the mud daubers do not defend their nest the way social wasps such as hornets and yellowjackets do.  They are very unlikely to sting, even when thoroughly aroused.  They may sting if mishandled. Control of these insects is not warranted since they normally pose little threat.  Rather, mud daubers should be regarded as beneficial, since they remove and use as prey many species of spiders which most people find disagreeable.
These wasps are interestig, but admittedly their nests can be unsightly in highly visible locations.  You can remove old mud dauber nests or even nests under construction with a putty knife.  The nests seem to come off in large chunks if not all together when carefully plied leaving very little outline.  It depends on the surface, but the flatter and sharper the tool you use will allow for more of the nest to pop off all at once.