Does there exist an infinite non-abelian group, such that all its nontrivial proper subgroups are isomorphic to $C_\infty$?
It is rater obvious, that if such group exists then it is generated by any non-commuting pair of its elements. However I failed to prove anything else about it.
This question was inspired by Ol’shanski theorem, that states, that for all primes $p > 10^{75}$, there exist continuum-many infinite non-abelian groups, such that all their nontrivial proper subgroups are isomorphic to $C_p$ (Such groups are called Tarski Monster $p$-groups).