Western wrestling, often referred to as Greco-Roman Wrestling or French Wrestling, is a sport that dates back to perhaps more than 15000 years ago. It is a form of combat that has been depicted in cave drawings, suggesting that it might be as old as humans themselves.
Many very famous and successful UFC fighters have had their beginnings in wrestling, like for example Daniel Cormier, one of the best heavyweights of all time.
Wrestling, though it is a category of its own, is a grappling-based martial art that focuses on disrupting the balance of the opponent in any given way (footwork, throws, sweeps, etc.) to put them on the ground and hold them there.
What makes wrestling highly effective is the speed at which takedowns are possible. There are no strikes in wrestling, but it makes up for that with all the types of takedowns practiced in any regular wrestling gym.
In a self-defense scenario, which usually happens in places like a darker street or some bar or disco, attackers tend to try to show their “dominance” by posing up for a fistfight, by kicking or trying to knock their opponent out.
This is where wrestling comes into play. Shooting for a double-leg takedown can happen in the blink of an eye and completely catch the opponent off guard and surprise them. Aside from that, a person not trained in wrestling or other ground- and grappling-based martial arts will have no clue what to do on the ground, so you can decide what happens from then onwards.
It is also a highly accessible martial art, available in most cities in the Western hemisphere, and in most schools in the U.S. as an extracurricular activity.
The one aspect of wrestling which forces it behind a couple of other martial arts is that it happens on the ground or very close to it. Though on a one-on-one situation, this is probably the easiest place to subdue an opponent for a skilled fighter, it might not be optimal in actual self-defense scenarios.
You can never know whether your attacker has some friends around, and if they do, you won’t have luck on the ground.
Nevertheless, wrestling is one of the most effective martial arts one can train for self-defense, since aside from all the practical and useful skills and techniques, it improves confidence, physical strength, and stability. All of these combined can help anyone overcome a large majority of untrained people.