The spider megacity was first found in 2022 by cavers who reported the find to scientists.
It was found in a network of limestone caves which have an entrance in Greece but cross over into the neighbouring country of Albania.
The sulphur caves have been formed by sulphuric acid when hydrogen sulphide a gas which smells of egg from groundwater reacted with oxygen.
Spiders are usually quite solitary creatures so communal webs are unusual, and scientists had never before documented a cooperative web woven by multiple species of spider.
What makes the find particularly unusual is one of the spiders, the barn funnel weaver spider, is known to be predatory and would usually eat smaller spiders like the sheet weaver spider which it was living and working with.
The researchers believe that the lack of light in the cave and the amount of food available were two of the reasons this didn’t happen.