"Take their secrets from their little ones”, a Lebanese saying that typically applies to family dynamics, serves in this case as a recipe for scientific discovery. Neutrinos have shown with their non-zero mass that the Standard Model is incomplete. Thus, understanding the properties and origins of neutrinos is crucial to our understanding of the Universe in general. IceCube, a cubic-kilometer neutrino observatory located at the geographic South Pole, explores neutrinos at extreme energies. And while it’s been successful in detecting an astrophysical flux of neutrinos extending to 10 PeV in energy, the origins are largely unknown. In this talk, I present various ways neutrinos can be used to probe the Universe. I will discuss a search using multiwavelength data to pinpoint cosmic colliders that may be responsible for accelerating cosmic-rays, and producing neutrinos. I will further discuss challenges and recent progress in cosmogenic neutrino detection as neutrino experiments enter a new energy frontier. Finally, I will highlight how we can use extraterrestrial neutrinos to probe dark matter, another great mystery that is yet to be reconciled with the Standard Model, and present recent progress in dark matter indirect detection with neutrinos.