A Christian is defined by a belief that Christ is who He claimed to be.

[color:"brown"]"The woman saith unto him, I know that Messias cometh, which is called Christ: when he is come, he will tell us all things. Jesus saith unto her, I that speak unto thee am he."[/color]
—John 4:25-26

The Bible provides numerous predictions about the future, one of those being that the "Churches" will "fall away" into a state of self indulgence close to the return of Messiah.

[color:"brown"]"For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears; And they shall turn away their ears from the truth, and shall be turned unto fables."[/color]
—2 Timothy 4:3-4

The delineation between true Church and false church is revealed by their doctrine, i.e., are they following fables or Scripture.

An example of this is that most of the largest denominations today have accepted homosexual behavior as acceptable. The idea that this behavior is acceptable to God is a "fable".

[color:"brown"]"Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God. And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God."[/color]
—1 Corinthians 6:9-11

So, the false churches today are those who do not endure sound doctrine. There are many and for those who know the Scriptures, they are easy to find.

Another false church is the catholic "tradition". It is, in fact, the ante-church. An interesting study is the Jesuit connection with the vatican and the city on seven hills.

Here is an introduction:
http://www.jesus-is-lord.com/anti1.htm

There is an astounding set of prophecies in the Bible that can only be properly understood by a conspiratorialist. More later if you wish.

[color:"brown"]"And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him."[/color]
—Revelation 12:9

A fast-growing number of those who have done their homework are recognizing these events unfolding right now.

It is a study that takes years to complete (for the skeptic like me) but it is well worth it.

So the answer is: "Doctrine".

Here are some developing parts of the puzzle. Beware. It does raise many more questions than it answers until you methodically tackle the questions one-by-one, at which point it becomes really interesting.

Return of the Nephilim, Chuck Missler
(unfortunately, this video is missing. I will do what I can to locate a copy soon)

From Freedom To Fascism

One Nation Under Siege

The Bar Code and the Mark of the Beast

Kennedy On Secret Societies

...for by your medication were all the nations deceived.

The Lincoln Assassination and the Jesuit Connection, Jon Eric Phelps (MP3)

The Sons of God and Biblical Prophecy, Michael Heiser

New Age Bible Versions