  The ${q}\bar{q}$ spectrum is studied within a chiral constituent quark model.
It provides with a good fit of the available experimental data from light
(vector and pseudoscalar) to heavy mesons including some recent results on
charmonium. The $0^{++}$ light mesons and the new $D$ states measured at
different factories cannot be described as $q\bar q$ pairs and a tetraquark
structure is suggested.
