The interaction of light with nanometer-sized solids in the context of nanophotonics provides the formerly inaccessible phenomena of sub-wavelength spatial focusing of optical radiation and the associated electric field enhancement. We extend this regime by 6 orders of magnitude in light intensity to the relativistic realm. We experimentally demonstrated the generation relativistic electron beams from nanotargets, their acceleration with electric fields beyond TV/m, i.e. the highest values ever used to accelerate electrons, and steering the electron properties with the waveform of the few-cycle laser fields. These results lead the way to the next generation electron sources delivering controllable, isolated relativistic attosecond bunches. and form the basis of a new research direction: relativistic nanophotonics.