In that battle, as in the battle for Sadr City, the Romans were constrained from a direct assault on the city. The Romans built a wall surrounding the city, cutting off the enemy from supplies. Eventually, the Celtic warriors inside the city were forced to try to attack the Roman wall and were defeated (as was a relieving force trying to attack the Romans from the other side). The Celtic leader Vercingetorix surrendered (he was taken to Rome as a prisoner and eventually strangled), and this cemented Julius Caesar's reputation as a brilliant commander.
That these two battles separated by over 2000 years and with completely different weaponry, still share the same basic plot, is to my mind amazing.