# Hollow Earth

> historical concept proposing that the planet Earth is entirely hollow or contains a substantial interior space

**Wikidata**: [Q649143](https://www.wikidata.org/wiki/Q649143)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Hollow_Earth)  
**Source**: https://4ort.xyz/entity/hollow-earth


## References

1. Freebase Data Dumps. 2013
2. BBC Things
3. KBpedia