The Irken Imperial Palace was the name of the palace on Irk from which Tallest ZIM and Empress Gazlene ruled over Irk. It was also the home of Prince Zagarius, Princess Zazlena, the Irk Senshi and ZIM's four guardians. The palace contains 912 rooms, including the palace kitchens, four banquet rooms, the royal couple's bedchamber, the servants' quarters and even the children's nursery. As shown in the movie and the events following the movie, the palace is located in the capital city and was built on the site of the former Tallest Tower. The interior and rooms are shown often, indicating that the Palace is where the Imperial Family and their protectors live. The Imperial Palace is also the crown jewel of Irk's capital city.
The palace is shown to be indestructible. Only those of the Tallest's family, his retinue and the Irk Senshi are allowed to enter the palace. Those who are not allowed are kept out by a barrier (the citizens may only come into the palace only in case of emergency, such as a frontal assault on the planet); Empress Gazlene uses her powers to send them out of the palace, though the Irkens' homes and businesses are also protected with a similar barrier so everyone is pretty much safe from attack. The palace is also the center of the Silicon Points.
No explanation was given as to its origin, but it could be seen in one of the last scenes of the movie, in the background of ZIM and Gaz's wedding.
In addition to the Empress' abilities to keep people out of the palace, the palace was protected by a translucent pink dome of energy surrounding it.