  We investigate macroscopic dynamical quantum tunneling (MDQT) in the driven
Duffing oscillator, charateristic for Josephson junction physics and
nanomechanics. Under resonant conditions between stable coexisting states of
such systems we calculate the tunneling rate. In macroscopic systems coupled to
a heat bath, MDQT can be masked by driving-induced activation. We compare both
processes, identify conditions under which tunneling can be detected with
present day experimental means and suggest a protocol for its observation.
