Time field

The Cracks were a series of splinters in the "skin of the universe," according to Prisoner Zero. The pattern of the Cracks is always the same, and the cause remains unknown. When discussing the cracks with Prisoner Zero, the Doctor stated that somebody must have opened the cracks. When he was asked if he knew what the cause was, the Doctor remained silent. (DW: The Eleventh Hour)

List of Cracks

• The first official crack was seen on Amy Pond's bedroom wall, which soon opened up to another area in the universe - an Atraxi prison. (DW: The Eleventh Hour)
• The crack was seen on the TARDIS monitor, which the Doctor looked at briefly before switching it off. (DW: The Eleventh Hour)
• Another was present within the hull of the Starship UK, a space ship inhabited by the residents of the United Kingdom. (DW: The Beast Below)
• The crack was seen in one of the Cabinet War-room(s) that the Prime Minister worked in during WWII. (DW: Victory of the Daleks)#
• Another crack is to be found in Flesh and Stone.

Crack Gallery

• 

  The first crack, seen on Amy Pond's bedroom wall. (DW: The Eleventh Hour)

• Secondcrack.png

  A crack shape seen on TARDIS's television. (DW: The Eleventh Hour)

• Crack 3.png

  The third crack, seen on the side of Starship UK. (DW: The Beast Below)

• Fourth crack.png

  The fourth crack seen in the wall behind the TARDIS as it dematerialises. (DW: Victory of the Daleks).

• Crack5byzantium.png

  The fifth crack seen inside the Byzantium. (DW: Flesh and Stone).

• 

  This image was produced for Series 5 publicity. A crack can be seen in the background.

• Another crack.PNG

  This crack is seen in the Tour of the TARDIS video.