A mysterious rumble in Whanganui last night is the latest in a long list of unexplained 'noises from nowhere'.
Last night Whanganui residents from Turakina to Waitotara said they heard a loud rumbling noise between 10.15pm and 10.30pm.
It was loud enough to shake the ground in Ratana Pa and reportedly set off the Civil Defence siren there.
Locals wondered if it had been an earthquake, but a spokesman for GeoNet, which records earthquake, tsunamis and volcanic eruptions, said the organisation's recording instruments had been quiet overnight.
"Just after 10pm there was a tiny earthquake that was so small it couldn't be felt or even located accurately," the spokesman said.
Whanganui residents are not the only Kiwis left baffled by mystery noises.
In June 2014, Aucklanders heard a series of "house-shaking" booms with no apparent source.
The booms later turned out to have been caused by the New Zealand Defence Force.
But not every mystery noise has been solved.
What's that noise?
1. Last month the booms were back around Onehunga and Mangere Bridge and the Defence Force said at the time they were not responsible this time around.
2. Another loud bang stumped residents in the Onehunga, Three Kings, Mt Roskill, Epsom and Mt Albert area on May 30 last year.
3. A mysterious humming noise was reportedly driving Aucklanders "bonkers" in 2006, when more than 30 people, most in Auckland and the North Shore, said they could hear a low, rumbling hum. One woman said the noise was so irritating she considered selling her home.
4. By late 2012 the hum seemed to have migrated down to Wellington, with at least 20 people living in the Mt Victoria, Mt Cook and Newtown areas complaining of a low hum. The noise was likened to someone blowing across the mouth of a bottle and a council spokesman said at the time he was "at a loss" to explain where it was coming from.
5. People have claimed to have heard a "weird, apocalyptic trumpet-like noise" around the world in recent years. People from all over the United States as well as Germany, Australia and even New Zealand said they had heard the noise coming from the sky. More than 150 videos of the strange sound were collected online, but no one had an answer for where it came from. Many suspected the "noise" was just an elaborate internet hoax.
6. In late, 2014 loud rumblings in the United States and the United Kingdom were heard which were apparently "powerful enough to shake the glass of windows," the BBC reported last December. Several possible theories for the noises were put forward at the time, but not confirmed.