Magma chamber
From Tardis Wiki, the free Doctor Who reference
An illustration of a magma chamber on a volcano. (TV: The Power of the Doctor [+]Loading...["The Power of the Doctor (TV story)"])
According to a diagram used by the Spy Master, a magma chamber was a part of a volcano. (TV: The Power of the Doctor [+]Loading...["The Power of the Doctor (TV story)"])
