Greenland sharks have the longest lifespan of any known vertebrate, estimated to be between 250 and 500 years. They are among the largest extant shark species, reaching a maximum confirmed length of 6.4 m (21 ft) long and weighing over 1,000 kg (2,200 lb). They reach sexual maturity at about 150 years of age, and their pups are born alive after an estimated gestation period of 8 to 18 years.
Absolutely everything about them is interesting. And as far as an entity, they are a fantastic role model. The world would be a much better place if we were all more like the Greenland Shark.