In the last decade the existence of exotic hadrons, which can not be explained as three-quark or quark-antiquark states has been firmly established, and today a significant number of systems are known that have to be classified as multiquark systems. Data collected at the LHCb experiment has led to a significant expansion of the list of these systems in the heavy flavor sector and ushered in an era of systematic investigation of the nature of unconventional hadrons. In this talk, we will review key discoveries in the field and discuss emerging questions and strategies for their resolution.
