Time travel is the ability to travel through time, whether to the past or the future. This is not a common power because of the extreme advantage a character using it has allows it to become a deus ex machina, thus spoiling dramatic tension. The Flash, Hourman, and Kang the Conqueror are some famous characters with the ability to time travel, each in their own ways. Superman has also shown an ability to time travel in pre-Crisis comics. Using the Dagger of Time, the Prince of Persia can manipulate the time stream to multiple effects.