There is a vast array of termite nests, although you will only see most of these in tropical regions. Termite mounds are in themselves great engineering feats (which may give ideas to us humans in constructing self containing cities). Many species that build such interesting nests normally live in forested areas and often cannot survive near man, as they have specialized nesting/feeding habits and diet, so it not likely you will be seeing many of them if you do not venture into the wilds.
Basically, there are 4 types of termite nest building models: 1) Wood nesters 2) Subterranean/hypogeal nesters 3) Arboreal nesters 4) Mound nesters.
Here are some interesting termite nest pictures from my personal collection:
The range of termite mounds out there is remarkable; what is interesting is termites are able to modify their nests according to their environment. Termites normally construct their nests during the night, or just after rain. They do not build the entire mound overnight, but constantly add to it and extending it gradually. Therefore a large mound can be many years old, possibly decades (termite queens and kings have long lifespans).
Termites are able to construct their mounds atop one another and this is one of the amusing things I’ve noticed. A mound can actually grow on top of another mound and yet, the different termites manage to keep out of each other’s way.
The nests of Microtermes is an example of termites living within the nest walls of another species (normally Macrotermes species). They construct simple nests (mostly small interconnected chambers), yet housing elaborate fungus gardens.
I have seen termites living within ant nests numerous times, and they do this by constructing their nests within the walls of the ant’s nest. Normally, these are small termite species (mostly from the subfamily Termitinae) living within the nests of large ants. While it may seem highly dangerous to the termites, the fact is, they appear to do quite well, feeding on the humus that make up the walls of the ant’s nest.
Arboreal termite nests are often built by Nasutitermes termites and normally located on tree trunks, between branch forks, and on branches; but they can also be found at ground level. Anywhere that is convenient for the termites, is where they will build their nests. In human habitation, some species of nasute termites do build carton nests underneath ledges and rooftops. Other types of termites that commonly build arboreal nests include Microcerotermes.