  We study the higher dimensional geometry of Berkovich spaces using open fiber
disks, which are given by open disks in a relative dimension $1$ fibration.
Inspired by birational geometry, we conjecture that the Berkovich skeleton is
the complement of the union of all open fiber disks, and prove this conjecture
for $\mathcal{X}$ admitting a strictly semistable model with semiample
canonical class.
