Naatan

In 36 BBY, a civil war among gangs decimated nearly all structures in the city and forced the inhabitants to live underground. More than a decade later, in 25 BBY, Obi-Wan Kenobi and his Padawan Anakin Skywalker went to Naatan with Jedi Master Yaddle to eradicate the stranglehold that the gangs had on the city and allow the populace to relocate back to the surface. However, the trio soon discovered that a prominent gang leader named Striker was actually Granta Omega, who was plotting to destroy the surface with a radioactive bomb. It was there that Master Yaddle sacrificed herself to save Naatan. After she died, Anakin felt partly responsible of her death because Granta Omega used him to lure her there.