  Strongly correlated many-body systems often display the emergence of simple
patterns and regular behaviour of their global properties. Phenomena such as
clusterization, collective motion and appearance of shell structures are
commonly observed across different size, time, and energy scales in our
universe. Although at the microscopic level their individual parts are
described by complex interactions, the collective behaviour of these systems
can exhibit strikingly regular patterns. This contribution provides an overview
of the experimental signatures that are commonly used to identify the emergence
of shell structures and collective phenomena in distinct physical systems.
Examples in macroscopic systems are presented alongside features observed in
atomic nuclei. The discussion is focused on the experimental trends observed
for exotic nuclei in the vicinity of nuclear closed-shells, and the new
challenges that recent experiments have posed in our understanding of emergent
phenomena in nuclei.
