The Baaj Temple is an area of the Baaj Ruins that you can reach later in the game after you have obtained the Airship, Fahrenheit. You will have to enter a set of coordinates under the input menu in order to reach it.
You need to travel to Baaj Temple after you have completed each of the Cloisters to obtain the Aeon Anima. Check out the Baaj Temple side quest section for details:
