A lot of people don't know the answer to that simple question.
There are a lot of similarities between Christianity, Judaism and Islam - the three main religious faiths in the world today. All three recognize one God: the Jews and Christians recognize Jehovah, while the Muslims call their god Allah. All of them discourage drunkeness, premarital sex, lying, cheating, stealing, murder. All of them encourage hospitality and kindness to those around us. Some say, "True, there are differences in specific laws and ceremonies, but that's just a matter of culture and taste. Strip them down to the basics and they are nearly identical, right?"
True, all three faiths have commandments and moral codes. Both the Law of Moses (Judaism) and the Qu'ran (Islam) attempt to show the way man can attain the favor of a holy God. The animal sacrifices, festivals, and laws of Judaism had to be perfectly obeyed in order to reach God. To fail in keeping one part of the Law was to fail in keeping all of it. In Islam, the Five Pillars (the shahadah (creed), daily prayers, almsgiving, fasting during Ramadan and the pilgrimage to Mecca) are the way to Allah. Do these things and you can achieve Allah's favor.
Christianity rose out of Judaism, of course, but the Jewish Law had one fatal problem: people! People were incapable of keeping the Law the way a perfect God demands. He demands perfection and people just aren't up to it. Since the penalty for failing to keep the law perfectly (sinning) under Jewish law was death(Romans 6:23), all people were doomed.
And that's what makes Christianity unique among world religions. It makes no pretense that man is capable of doing enough of ANYTHING to reach a perfect, holy, almighty God. In fact, the apostle Paul tells us in Galatians 3:24 that the Law was given as a tutor to teach us that we are incapable of doing what it takes to reach God on our own. That's ok though, because he goes on to say in verse 25 that we are no longer under that tutor. Christ fulfilled the requirements of the Law, then paid the penalty of death for us at the cross.
Christianity is the not a list of rules that help man reach God. It is the story of an almighty God that loved His creation so much that He reached down to us.
Instead of climbing out of the hole of sin I have created for myself, God reaches down and pulls me out...all I have to do is take His hand. And that makes all the difference.