  We demonstrate that fast removal of many electrons uncovers initial
correlations of atoms in a finite sample through a pronounced peak in the
kinetic-energy spectrum of the exploding ions. This maximum is the result of an
intricate interplay between the composition of the system from discrete
particles and its boundary. The formation of the peak can be described
analytically, allowing for correlations beyond a mean-field reference model. It
can be experimentally detected with short and intense light pulses from
4th-generation light sources.
