Planet Leto is a world in the Delta Pavonis star system.
It was originally a barren place, until Professor Antony Leto chose it as a test subject for his experimental terraforming procedure. This was not entirely successful, as he created "an almost planet-wide breeding ground for tornadoes, cyclones, you name it."
The planet also had an extremely unbalanced ecosystem, with many species being introduced from Earth. In 2204, Professor Karen Morant uncovered evidence that there had been diverse species native to the planet which had been illegally almost wiped out by the terraforming process - effectively destroying one world to create another.