The Roman statesman, Appius Claudius Caecus, made the decision to pave the way in 312 BCE, which was why it was named "Via Appius." The road was paved during the Samnite wars, the three wars between the Roman Republic and the Samnite tribes. The object of the road was to allow a large movement of military forces from place to place, eventually reaching the city of Brindisi in southern Italy, where it also received its original name - VIARUM REGINA, the "Queen of the Road."
As for the catacombs, they were built out of necessity. The Christians in Rome were persecuted and so when they had to bury their loved ones, they did it underground to protect their graves from desecration. What remains of these graves today are ruins, which you can see throughout the Via Appia and are called "catacombs." The tour is fascinating and instructive.
There was a huge organization of slaves who planned to escape from the Gladiators' school. The reason is the abuse they underwent from their trainer, Batiatus. He was informed of the escape and only 78 gladiators managed to succeed, equipped with kitchen knives they had taken from the compound. The weapons later served them when the local guard tried to stop their escape. This escape led to a huge revolt that caused great trouble for the Roman army. The revolt was led successfully by Spartacus, who established a mighty army and led them to victories over the Romans. However, in the end the Romans defeated him and captured many of the rebels.
Under the laws of the Republic, where rebels are punished with execution, some 6,000 slaves were crucified along this very road, in order to instill fear in the hearts of others. Everyone who passed by Via Appia saw rows of crosses, with the bodies of Spartacus's soldiers on them. This was the fate that awaited traitors in Rome.