  In this white paper we explore the capabilities required to identify and
study supermassive black holes formed from heavy seeds ($\mathrm{M_{\bullet}}
\sim 10^4 - 10^6 \, \mathrm{M_{\odot}}$) in the early Universe. To obtain an
unequivocal detection of heavy seeds we need to probe mass scales of $\sim
10^{5-6} \, \mathrm{M_{\odot}}$ at redshift $z \gtrsim 10$. From this
theoretical perspective, we review the observational requirements and how they
compare with planned/proposed instruments, in the infrared, X-ray and
gravitational waves realms. In conclusion, detecting heavy black hole seeds at
$z \gtrsim 10$ in the next decade will be challenging but, according to current
theoretical models, feasible with upcoming/proposed facilities. Their detection
will be fundamental to understand the early history of the Universe, as well as
its evolution until now. Shedding light on the dawn of black holes will
certainly be one of the key tasks that the astronomical community will focus on
in the next decade.
