  In recent years nanoscale coherent imaging has emerged as an indispensable
imaging modality allowing to surpass the resolution limit given by classical
imaging optics. At the same time, attosecond science has experienced enormous
progress and has revealed the ultrafast dynamics in atoms, molecules, and
complex materials. Combining attosecond temporal resolution of pump-probe
experiments with nanometer spatial resolution would allow studying ultrafast
dynamics on the smallest spatio-temporal scales but has not been demonstrated
yet. Unfortunately, the large bandwidth of attosecond pulses usually hinders
high-resolution coherent imaging. Here we present a robust holography-enhanced
coherent imaging method, which allows combining high quality and high spatial
resolution coherent imaging with a large spectral bandwidth. By implementing
our method at a high harmonic source we demonstrate, for the first time, a
spatial resolution of 34 nm (2.5 {\lambda}) in combination with a spectral
bandwidth supporting a Fourier limited pulse duration of only 380 as. The
method is single-shot capable, additionally retrieves the spectrum from the
measured diffraction pattern, and is thus immune against shot-to-shot
fluctuations. This paves the way for an ultrafast view on nanoscale dynamics
e.g. ultrafast charge transfer or ultrafast spin currents being relevant for
Petahertz electronics and future data storage.
