An alien conspiracy story.
Eons past, an agreement between two alien races that visited earth has allowed humans to flourish. One of these alien races still has active machines on earth hidden from humans, & working to unknown ends via termites. When Martians get too interested in earth, these dormant alien artifacts force them to retreat & leave earth to humans.
Fact sheet.First published: Amateur Science Fiction Stories, March 1938.
Related: Stories of Arthur Clarke.
Note: Why is this post so short?