Do you swim in the ocean, or are you afraid of sharks? Many humans have a strong fear of sharks. This is an irrational fear, since the chance of being attacked by a shark is extremely low. In a typical year, fewer than 20 people worldwide die from a shark attack. There are hundreds of shark species, but only three are typically to blame for attacks involving humans. The tiger shark, the bull shark, and the great white have all attacked and killed humans over the years. Shark attacks are classified as either provoked or unprovoked. A provoked attack is when a human initiates the attack. An unprovoked attack is when a shark initiates an attack. While shark attacks are extremely rare, humans kill an estimated 100,000,000 sharks a year. Many sharks are fished for their fins, and thrown back in the ocean to die. The fins are mainly used for a delicacy known as shark-fin soup, which can cost up to $100 a bowl. Some fins are considered trophies, and can be worth thousands of dollars.