Arch of Titus
Interior of the Arch of Titus
The inside of the arch has relief (raised) carvings showing the victory parade when Titus got back to Rome.
Here's a closeup of the carvings:
You can see the Roman soldiers carrying a huge menorah (candlestick) which they had taken from the Jews. They are about to go under a triumphal arch.
On the other side, the Emperor Titus (whose head is missing now) rides in a chariot drawn by four horses.
The Colosseum & the Roman Forum, by Martyn Whittock (2002). Easy reading.
The Roman Forum, by Michael Grant (1970). Out of date, but Michael Grant is an entertaining writer with a simple style which teenagers may appreciate.
Ancient Roman Art, by Susie Hodge (1998). Easy reading.
Roman Art: Romulus to Constantine, by Nancy and Andrew Ramage (4th Edition 2004). The standard textbook.