  We review certain properties of confinement with added focus on the ones we
study with holography. Then we discuss observables whose unique behavior can
indicate the presence of confinement. Using mainly the Wilson loop in the
gauge/gravity formalism, we study two main features of the QCD string: the
string tension dependence on the temperature while in the confining phase, and
the logarithmic broadening of the flux tube between the heavy static charges
that turns out to be a generic property of all confining theories. Finally, we
review the k-string bound state and we show that for a wide class of generic
theories the k-string observables can be expressed in terms of the single meson
bound state observables.
