Why does the Radley place fascinate Scout, Jem and Dill?
The stories about Boo Radley would pique the interest of just about anyone, be it children or adults. Although Atticus and Miss Maudie have a rational outlook on the real Boo Radley, other adults (particularly Miss Stephanie) share the belief that their mysterious neighbor is the ghoulish character that local legend dictates. Jem and Scout are used to the stories, and they pass the house routinely; but when Dill arrives in Maycomb, he ignites further curiosity among the children. It's a new type of distraction for the imaginative Dill, who often stands alone and studies the Radley House, no doubt making mental comparisons between Boo and the movie villain, Dracula. The summers are slow in Maycomb, and the children find that there is little else more exciting than wondering about the peculiarities of their unseen neighbor.
Boo Radley himself is seen as such an anomaly by everyone in the town, the same goes for Scout, Jem and Dill. The house is always shut up and they hear rumors about Boo and his past as well as the simple mysteriousness of the house that is never open and no one seems to come in and out. Because they spend so much time near the house, the mystery of it gets to a point where it is almost overwhelming. As most children, they want to make sense of the world around them and there is this big black hole of mystery that draws them in inexorably.