Two-particle correlations at low relative velocity probe the space-time structure of high-energy collisions at the fermi scale. Huge systematics have been developed over two decades-- both in time and in collision energy. At RHIC, these femtoscopic measurements have been explored in much greater breadth and detail than was possible in the preceding two decades. By combining high statistics, large acceptance, multiple kinetic and entrance-channel cuts, and particle species combinations, femtocopy at RHIC has become a precision tool. Furthermore, the possibility to study p+p collisions in the same environment - and with the same techniques - as A+A collisions allows direct comparison between these systems for the first time. I will discuss what we might look for at the LHC, in the context of the past 20 years' worth of systematics.