If you want to be able to defend yourself without weapons, I recommend these martial arts:

• Krav Maga

• Boxing

• Judo

Krav Maga will teach you how to recognize weapons, and how to fight dirty. Boxing will teach you head movement, footwork, how to throw punches, and how to dodge hands. Finally, Judo gives you the ability to deal with people that grab you. They grab you, you can toss, or trip them, and most people will be done after hitting the floor. But more importantly, if you go to the floor, you'll know how to survive there.

There are other arts you can study, but for the streets, I think these three arts are a must. Study them for a few years, and you'll be better at fighting than most. Of course, avoid fights if you can. Use your brain. Not every fight is winnable.