The mosaic is the so-called Alexander Mosaic, found at Pompeii (now in the archaeological museum in Naples), thought to be a reproduction of an earlier painting.
Top Ten Finds in Archaeology for me.
1. Pompeii (The Villa of the Papriri)
2. The Clay Army of Shang Han of China
3. The Swedish warship Vasa.
4. The tomb of King Herod
5. The Royal Tombs at Tanis (the silver mummy)
6. King Tut in the Valley of the Kings.
7. The Etruscan Tombes in Italy.
8. The Pyramides in Northern Sudan
9. the Cities of Zimbabwe
10. The Mound builders tombs in Ohio, America.