  The dark matter problem is almost a century old. Since the 1930s evidence has
been growing that our cosmos is dominated by a new form of non-baryonic matter,
that holds galaxies and clusters together and influences cosmic structures up
to the largest observed scales. At the microscopic level, we still do not know
the composition of this dark, or invisible matter, which does not interact
directly with light. The simplest assumption is that it is made of new
particles that interact with gravity and at most weakly with known elementary
particles. I will discuss searches for such new particles, both space- and
Earth-bound including those placed in deep underground laboratories. While a
dark matter particle hasn't been yet identified, even after decades of
concerted efforts, new technological developments and experiments have reached
sensitivities where a discovery might be imminent, albeit certainly not
guaranteed.
