Public domain. Cover image from Project Gutenberg ebook #68783. The swamp was upside down by Murray Leinster Download .m4b · 99 MB How to listen → · Problem with this narration? Let us know → Narrator Walter — American Narrator (en-US) Length 1 hr 37 min Language English Added November 6, 2026 Source ebook Project Gutenberg License Public domain NonfictionScience Fiction