Download the rule for Small World: Underground or any other documents (scenarios, goodies, pedagogical sheet, erratum, ...). 2 PDF files are available.
pdf https://cdn.1j1ju.com/medias/68/07/03-small-world-underground-rulebook.pdf
4 Maps of Small World Underground, contained on two double-sided boards, one for each of the four possible player configurations.
5.11 Mo - In Englishpdf https://cdn.1j1ju.com/medias/58/1e/a2-small-world-underground-regle.pdf
2 plateaux de jeu réversibles, soit 4 mondes de Small World Underground différents, correspondant chacun à un nombre de joueurs.
4.48 Mo - In French