Niflheim vs Tophet

Niflheim

name
  • In Germanic and Norse cosmology, the Norse underworld, location of the domain Hel and of the realm of Hel, the goddess of the dead. 

Tophet

name
  • Hell, Gehenna. 

  • A location near Jerusalem in the valley of Gehenna where children were burned alive as sacrifice. 

How often have the words Niflheim and Tophet occurred in a corpus of books? (source: Google Ngram Viewer )