When Christ the Lamb breaks the fifth SEAL, John sees under heaven's altar the souls of martyrs slain for their testimony. They want God to avenge their blood quickly, but are told to wait a little longer until other martyrs join their number.
The breaking of the sixth SEAL brings all kinds of cataclysms, such as falling stars. All the peoples of the earth hide in caves and call out to the mountains and rocks, "Fall on us and hide from God and the Lamb! The great day of their wrath has come!"