The Petranaki arena, also known as the Arena of Justice and commonly referred to as the Geonosis execution arena, was a large structure on the planet Geonosis. It was used for Petranaki gladiatorial battles between creatures and sentient beings. Ten years after the Invasion of Naboo by the Trade Federation, the arena was the site of the attempted execution of Jedi Obi-Wan Kenobi and Anakin Skywalker and senatorPadmé Amidala. A team of 212 Jedi led by Jedi MasterMace Windu was sent to the arena to rescue the trio, but were attacked by battle droids belonging to the Confederacy of Independent Systems. Most of the Jedi were killed before being rescued by the newly formed Grand Army of the Republic, marking the beginning of the Clone Wars.