Short answers, pulled from the story.
The ruins of ancient Memphis are located near the present-day village of Mit Rahina, in Badrashin county, Giza Governorate, about 20 kilometres south of Cairo, on the west bank of the Nile. The site is open to the public as an open-air museum.
According to the priest and historian Manetho, writing in the early third century BC, Memphis was founded by King Menes, the first ruler to unite Upper and Lower Egypt. The first royal palace was attributed by Manetho to Hor-Aha, Menes's successor, who built a fortress of white walls there. Some Egyptologists identify Menes with the historical king Narmer, though an inscription found in 2012 shows that the predynastic king Iry-Hor visited Memphis two generations before Narmer.
The word Egypt derives from the ancient name of Memphis's great temple, Hut-ka-Ptah, meaning "Enclosure of the ka of Ptah". The Greeks rendered this name as Aigyptos, which passed through Latin into the modern English word Egypt.
The Rosetta Stone is one of the stelae produced under the Decrees of Memphis, issued in 196 BC by Ptolemy V. The decrees were engraved in three scripts, Demotic, hieroglyphic, and Greek, so they could be read by all. The Rosetta Stone's trilingual inscription allowed scholars in the nineteenth century to decipher ancient Egyptian script.
Memphis lost its economic significance in late antiquity following the rise of coastal Alexandria, which better served the needs of the Ptolemaic and then Roman rulers. The Edict of Thessalonica in 380 AD, which made Nicene Christianity the sole religion of the Roman empire, ended the ancient religious cults that had sustained the city's identity. By 641 AD, when the Arabs founded Fustat nearby, Memphis was largely abandoned and its stones were quarried to build the new settlement.
The limestone colossus of Ramesses II, about 10 metres in length, was discovered in 1820 near the southern gate of the Temple of Ptah by Caviglia. Because its base and feet were broken off, it is displayed lying on its back in the open-air museum at Memphis. A second colossus found the same year was restored in the 1950s to a standing height of 11 metres and was moved in January 2018 to the entrance of the Grand Egyptian Museum.