There are not any Batmen though...and being a Martial Artist and having a black belt don't mean crap. I knew an olympic wrestler and third degree black belt in Kung Fu who almost got killed in a bar fight with a guy who was a first degree alcoholic with a bad temper. Batman is not real. In order to wage a war on crime successfully with just your fists, you would need a lot. A no you can't just train yourself, most athletes professional or otherwise are genetically gifted first and foremost. Chances are if you are doing Martial Arts in some local school you are not a genetic freak like these guys. And even if you are, and even if you could master gymnastics, martial arts and strength training, you would still need some form of wealth to become anything more than a Gaurdian Angel.
In order to have the agilit, strength, speed and fighting prowess you would have to be incredibly genetically gifted. You would have to be naturally very athletic in at least two of those areas. If your not I can tell you no amount of training will make you so. Bruce Lee was never slow...but consequently he was never that strong either. Arnold Swarzenegger could bench press same vehicles, but he could not fight his way out of a paper bag (metaphorically speaking). People devoute their lives, LIVES to mastering ONE of these things, not all ONE. Take it from an Athlete in both HS and College. It is impossible, impossible to be physically capable enought to accomplish what Batman accomplishes. Let me re-enforce this because I don't think it gets through. You will NEVER be as good as Batman, NEVER. Even the best combatants like Randy Coutour still can be beaten. Still cannot take on more than say two guys at once. There is a reason Bruce Lee kept guns in his house, he obviously was not relying on his Martial arts to save him.
How exactly would you find crime, just walk around. How would you combat the mob, start asking questions. They their are a few vigilante's running around, most of whom are pathetic jokes. Like the Brooklyn Avenger who is just some crazy guy in a cape they keep arresting. The rest are Guardian Angels for the most part
Furthermore you can't combat a man with a gun (without a gun yourself). The higher up you go in fighting the more and more this becomes apparent. Fighting on TV and comics is far different. If you have a bullet proof vest I will shoot you in the face and there is NOTHING you can do about it. Bullets travel FAST, and unless he is some coked out homeless mugger he will not hestitate to pull the trigger. Then you will be dead.
I agree with the initial posts
Could there be a Batman, yeah...but it would only last one night