Sanctum sanctorum is a very special room in some religious buildings, like temples or mosques. It is the most sacred room, where the most important religious objects are kept and where the most important rituals take place.
Imagine your bedroom as your sanctum sanctorum. It is your most special place where you keep all your favorite things, like your toys, books, and blankets. You feel very happy and safe in your bedroom and sometimes, you want to be left alone to play or rest in your sanctum sanctorum.
Similarly, in a temple, the sanctum sanctorum is the most holy and sacred place where people can pray and worship their gods. The room is usually decorated with beautiful artwork, flowers, and candles. The most important objects, like statues of the gods or important books, are kept in the sanctum sanctorum.
Only certain people are allowed to enter the sanctum sanctorum, like priests or religious leaders. They usually have to follow certain rules, like removing their shoes or washing their hands before entering. It is believed that the sanctum sanctorum is a very special place, and it is very important to show respect and honor its holy status.