Proper noun
Helheim
(Norse mythology) The realm of the dead, (also known as Hel), the domain of the goddess Hel. Located beyond Niflheim, (one of the Nine Realms).
The Helheim glacier calving, sped up 20x. Source: Internet
The Doctor then used his TARDIS, to divert his TARDIS in the past, to arrive on Helheim in the first place. Source: Internet