
Southern wood ant - nest construction, Heeswijk-Dinther, Netherlands
I usually don't really know what to do when seeing thousands of ants going about their ways in what appears to be chaos. Best to follow just one ant, such as this one delivering some large organic material (a nut?) to the nest building crew.
The nest is an ecosystem on its own, and not just for the ants. Specific soil animals live in these enormous nests as they are warmer and dryer than the normal soil.

''Formica rufa'', also known as the southern wood ant or horse ant, is a boreal member of the ''Formica rufa'' group of ants, commonly found throughout much of Europe in both coniferous and broad-leaf broken woodland and parkland.