A piece of board leaning against the wall initiated an ant trail leading upwards. Photo taken on 18.09.2016 (Wojciech Stephan).

 
 
  Part of: Rutkowski T, Maák I, Vepsäläinen K, Trigos-Peral G, Stephan W, Wojtaszyn G, Czechowski W (2019) Ants trapped for years in an old bunker; survival by cannibalism and eventual escape. Journal of Hymenoptera Research 72: 177-184. https://doi.org/10.3897/jhr.72.38972