  We have observed the BL Lac object Markarian 501 at 1.4 GHz with the High
Sensitivity Array and at 86 GHz with the global VLBI mm array. Thanks to the
great resolution and sensitivity provided by these instruments, we probe
regions of the radio jets never accessed before. The new data at 1.4 GHz allow
us to map the one-sided jet at large distances from the core, and to constrain
jet properties thanks to the high jet to counter-jet brightness ratio. The 86
GHz data give us a high resolution image of the nuclear region. Putting
together these new results and available published data we discuss the
properties of this source from sub-parsec to kiloparsec scales.
