  Multiple scales coexist in complex networks. However, the small world
property makes them strongly entangled. This turns the elucidation of length
scales and symmetries a defiant challenge. Here, we define a geometric
renormalization group for complex networks and use the technique to investigate
networks as viewed at different scales. We find that real networks embedded in
a hidden metric space show geometric scaling, in agreement with the
renormalizability of the underlying geometric model. This allows us to unfold
real scale-free networks in a self-similar multilayer shell which unveils the
coexisting scales and their interplay. The multiscale unfolding offers a basis
for a new approach to explore critical phenomena and universality in complex
networks, and affords us immediate practical applications, like high-fidelity
smaller-scale replicas of large networks and a multiscale navigation protocol
in hyperbolic space which boosts the success of single-layer versions.
