From Warhammer 40k - Lexicanum
Mettalum Olympus was an Imperator Titan commanded by Princeps Goethe. It managed to almost single-handedly hold back a Tyranid invasion on the ash-choked plains of Horst Prime. The titan was surrounded by an entire horde of Hierophant bio-titans and its plasma reactor was breached by their frenzied attacks. The resultant explosion vapourised everything for a kilometre around and left a crater that is still visible from orbit.
- 1: Codex: Tyranids (5th Edition), pg. 81