  Recent discovery of persistent revivals in quantum simulators based on
Rydberg atoms have pointed to the existence of a new type of dynamical behavior
that challenged the conventional paradigms of integrability and thermalization.
This novel collective effect has been named quantum many-body scars by analogy
with weak ergodicity breaking of a single particle inside a stadium billiard.
In this overview, we provide a pedagogical introduction to quantum many-body
scars and highlight the newly emerged connections with the semiclassical
quantization of many-body systems. We discuss the relation between scars and
more general routes towards weak violations of ergodicity due to "embedded"
algebras and non-thermal eigenstates, and highlight possible applications of
scars in quantum technology.
