This is the facade, or front entrance, to the palace
March 2017 - Vespasian, the first emperor of the Flavian Dynasty in Rome, had been popular because he lived plainly and acted like he was equal to everyone else. His son Domitian was different. He wanted everyone to know that he was the Emperor and he was more important than everybody else. Besides, Roman government was getting pretty complicated, and they really needed a big building where all the different slaves and freedmen who worked for the government could have offices. So in the 90s AD, Domitian had his architects build him a great palace on the Palatine hill in Rome. (We get our word "palace" from the name of the hill).
Domitian was able to build a huge palace relatively quickly and cheaply because his architects used a new building method (which Nero had also used in his Golden House) of bricks and concrete. Over the bricks, Domitian had marble facings, to make it all look like marble, but over the years most of the marble has been stolen away, so now only the brick and concrete are left.
Here's a place where some of the marble is still in place on the wall.
Domitian's palace had three main areas. The first was a public courtyard, with big public rooms all around it. This was where Domitian met visiting ambassadors from other countries, or made important public announcements, or held big formal parties. There was a huge throne room on one side of the courtyard, and a huge dining room on the other side, and lots of smaller rooms as well for meetings and conferences.
Domitian's throne room was so big that we can't understand how he could have put a roof on it without the roof falling in, using Roman technology. Some people think the throne room must have had a wooden roof, while others think it could have been done in brick and concrete. Today, none of the roof is left to tell us.
Learn by doing: build a big room out of Lego and figure out how to put a roof on it
A Private Courtyard of Domitian's Palace
You Are in Ancient Rome, by Ivan Minnis (2004). For younger kids.
Ancient Rome: A Guide to the Glory of Imperial Rome, by Jonathan Stroud (2000). A day as a time-travelling tourist in ancient Rome, for kids.
Houses, Villas, and Palaces in the Roman World, by Alexander McKay (1998). A good section on Domitian's palace.
Roman Architecture, by Frank Sear (1983). The standard college textbook.
The Architecture of the Roman Empire: An Introductory Study, by William MacDonald (1982). Actually not so introductory, but it's got great illustrations that really make the building techniques clear. A great section on the roofing of Domitian's throne room.
Roman Imperial Architecture, by J. B. Ward-Perkins (1992). A more detailed textbook, and harder going.