The residual Julia set, denoted by J r (f ), is defined to be the subset of those points of the Julia set which do not belong to the boundary of any component of the Fatou set. The points of J r (f ) are called buried points of J(f ) and a component of J(f ) which is contained in J r (f ) is called a buried component. In this paper we survey the most important results related with the residual Julia set for several classes of functions. We also give a new criterium to deduce the existence of buried points and, in some cases, of unbounded curves in the residual Julia set (the so called Devaney hairs). Some examples are the sine family, certain meromorphic maps constructed by surgery and the exponential family.