In Boom Town, the Ninth Doctor refers to the Rift in the plural, indicating that there are others elsewhere. In series 3 episode The Sound of Drums (2007), the Master (John Simm) also refers to the Doctor sealing the rift at the heart of the Medusa Cascade, deep in space. The Daleks later planned to make use of this rift in spreading their Reality Bomb (Journey's End, 2008). When explaining the prevalence of foresight abilities in Pompeii, the Doctor explains Mount Vesuvius temporarily opened a Rift in time and space, which accounts for this, in the episode The Fires of Pompeii (2008). In the series 6 episode The Doctor's Wife (2011), the Eleventh Doctor (Matt Smith) travels through a time rift to a location outside the universe. He comments that his TARDIS should refuel by virtue of being exposed, as with the Cardiff rift, to temporal energies.