Currently in Museo Nazionale Prenestino in Palazzo Barberini, Palestrina, Italy.
Dated to around 100 BC this is what we term Hellenistic mosaic, made using very small tesserae. Set as part of a grotto it measures 5.85 m by 4.31m It was discovered in 1507 and was moved so there have been various restoration works. This always causes a problem when you look at a mosaic with a view to making a copy of all or sections of it is you can never be sure which bits are original and which are copies.
It's interesting in how it depicts so many different scenes of life around the Nile at that time.
All photos copyright and by permission of Zane Green 2013