Scientists have confirmed that the eruption of the underwater Hunga-Tonga Hunga-Ha'apai volcano in January this year was truly off the scale.
It was the biggest atmospheric explosion registered on Earth in more than 100 years - so big it could be seen from space.
It produced a record volcanic plume and a tsunami which devastated parts of nearby Tonga.
A research team from NIWA recently travelled to the volcano to take a close up look.
NIWA marine geologist Kevin MacKay was the voyage leader, he talks to Jesse.