Ants and termites both build nests. The nests must house a queen and the many attendant workers and brood. The general structure of the nest, chambers connected by tunnels, is similar due to the similar needs of social insect colonies. The most notable difference between ant and termite nests is that termites construct portions of the nest, most ant species do not. Ants primarily excavate soil with no other construction. However, in some cases ants will construct a lining for their nest. Ant mounds can be a meter in height and quite extensive. Although impressive, they are the product of soil deposition rather than directed construction.
Some termite species build structures above ground that are several meters high. These structures are not the products of soil excavation but a mixuture of termite saliva, feces and soil particles. Most termite species create pillars for structural support within their nests. Even those few species that do not construct pillars will create a lining for the nest. Termites that tunnel in wood may construct protective structures such as mud tubes that allow termite foragers to access water in relative safety.
Termite and ant nests are the result of independent evolution in two groups that arrived at a similar social condition by separate paths. Comparing the structures of termites and ants can give insights into the constraints how the solutions to similar problems evolved.