Whales are the biggest animals in the world. The average length of adult blue whale is around 25 meters. Most people will be scared if they meet a whale, but this animal is usually safe for people. Of course, it may injure people because it is big and powerful. However, this happens only in case they are scared or feel threatened. Like all animals, whales protect their young generation, and may hurt other species as well as people or boats. Still, many people like to swim with them because it is an unforgettable experience.