Women inspect the insides of the jaws of a megalodon, an extinct species of the shark, as they visit the international exhibition titled "Planet Shark: Predator or Prey" at the Military-Historical Museum of Artillery, Engineer and Signal Corps in St. Petersburg, Russia, on Oct. 31. The exhibition includes collections of pristine fossil specimens, jaws, hunting and commercial fishing equipment, full size casts and models of different sharks, according to organizers. (Alexander Demianchuk/Reuters)