A large training dojo was built during the Clone Wars by the Jedi Order on sublevel nineteen of the Jedi Temple. It was built to replicate the many different terrains Jedi might find themselves in during the war.
It reached completion a year later, days before the Battle of Kothlis in 21 BBY. Built to replicate the terrain Jedi might face on any number of missions, the dojo had an extensive array of atmospheric and gravitational controls. The dojo was designed with a set target that had to be retrieved before those undertaking the mission were incapacitated - with non-lethal force - by the hordes of battle droids swarming the area.
Following the Kothlis debacle, Jedi Master Taria Damsin led a group of twenty five senior Padawans in a competition through the new dojo. With Padawan Ahsoka Tano leading twelve students as Green Group, and Master Damsin leading thirteen students as Blue Group, the two raced across the terrain in order to be the first to reach the beacon within the mini city.
Given a head start due to their fewer numbers, Green Group made their way across the groundquake portion of the terrain and into a dense jungle clouded with mosquito droids. As rain pored down, Padawan Laksh'atz was disqualified as the mosquito droids overwhelmed the group. Making their way to the river banks, the Padawans fought off modified B1 battle droids, losing T'boor in the battle. Making it over a ravine, through zero-gravity pockets and droid-infested bogs, the group made it to a mini city while losing Baggro and five others. Rushing against the three active members of Damsin's team, both teams eventually made it to the top of the tower together and tied in the competition.
Filling up the entirety of Sublevel Nineteen, the new training dojo's terrain consisted of a plain of quake-ground, a jungle, a river and ravine, and a four block mini-city, as well as pockets of zero-gravity and heavy atmospheric manipulation. Using battle droids recovered from real battles, the arena was designed to replicate the trials facing the Jedi while still within the confines of the Temple.