  We study scenarios in which there is a hierarchy of two sets of large
compactified extra dimensions. One particularly interesting case has a single
millimeter size extra dimension and five TeV^{-1} size dimensions. The Standard
Model gauge bosons have Kaluza-Klein excitations with respect to one of the TeV
scale dimensions. We discuss astrophysical constraints on this scenario, as
well as prospects for signals at future high energy colliders.
