In Lord of the Flies, Simon is not like the other boys. He is very helpful and kind and is the one who helps Ralph build the shelters. He finds the growing conflict between Ralph and Jack to be unsettling and likes to have time alone. He does not have any fear of the darkness and so has to admit that he is the one roaming around at night in the dark because some of the "littluns" are convinced that a "beastie" is lurking.
After the signal fire goes out and Ralph and Jack have been arguing, Simon looks "from Ralph to Jack... and what he saw seemed to make him afraid." Simon is very perceptive and aware that the growing tension is more about the boys' relationships and struggles than it is about a beast. He is able to collect his thoughts when he is alone. Simon is in this special place when he hallucinates, thinking that the pig's head on a stick represents the beast speaking to him when it says "Fancy thinking the Beast was something you could hunt and kill! ... You knew, didn't you? I'm part of you?" He has realized why the boys are so afraid and why they think they have seen the beast and he wants to tell them about the dead parachutist.
Simon's special place is therefore significant because it helps Simon understand his surroundings but it is also the place where Jack killed the pig and left the "Gift for the Darkness." It therefore helps the reader prepare for what will follow when Simon tries to share the information with the boys and is killed for his trouble, mistaken for the beast. This is ironic and confirms that, despite the best efforts of some of the boys, they cannot defeat the savage within Jack and his hunters.