Can You Figure Out This Riddle??

Back in the time of Oedipus, the Great Sphinx of Giza used to ask riddles when ever somebody passed by. If the person answered correctly well, they got to live. But if they didn't answer correctly, well, SPLAT!!! Your dead...So you better answer correctly!!
I. Once when Oedipus was walking by a Sphinx, he heard the Sphinx talk and Oedipus thought he was out of his  mind, but he wasn't. So he was basically like "are you talking to me?" So Oedipus listened as the Sphinx asked him the riddle: "In every window and every door crack, round and round the house and never a crack. What am I?"So Oedipus had to think for a min. because well you know. If he got it wrong he was dead. Finally Oedipus answered " the wind" and the Sphinx was so amazed at Oedipus and so surprised that someone finally got his riddle right. So the Sphinx let Oedipus live.