The small valley between the hills of Palatine and Capitol is called
Velabro.
The Velabro was initially a small river that went down from the hill of Viminale,
through the Forum, and ended up in the Tiber. For a long time a marshy area,
it was drained at the beginning of the reign of the Etruscan kings.
An important way goes through it,
the Vicus Tuscus 
, that comes to the Forum between
the Basilica Julia and the temple of Dioscuri. This way goes in the front of the
temple
of deified Augustus, at the top left. At last, alongside the walls of the Palatine,
you see at the top of the picture, a part of the great
wheat warehouses,
which were probably built by Marcus Agrippa and partly by Germanicus, Augustus’s grandson.
The way that goes alongside the Capitol in the centre of the picture is the
Vicus Iugarius.

.