Sahih Muslim Book 40, Hadith Number 6813.
Chapter : The description of hell and the intensity of its heat and torments.
Abu Huraira reported: We were in the company of Allah’s Messenger (may peace be upon him) that we heard a terrible sound. Thereupon Allah’s Apostle (may peace be upon him) said: Do you know what (sound) is this? We said: Allah and His Messenger know best. Thereupon he said: That is a stone which was thrown seventy years before in Hell and it has been constantly slipping down and now it has reached its base.