Scientists from GNS Science in New Zealand have discovered a volcano so big they are struggling to find words to describe it.
Jenny Barretto and Ray Wood from GNS Science, along with John Milsom from the UK, were studying the Philippines' continental shelf when they discovered a caldera three times as big as Lake Taupo.
The gigantic caldera has been named Apolaki, which means "giant lord" in Filipino.
"Apolaki is so large that no comparison is available on Earth - during the review process, scientists had to draw on comparisons with calderas from Venus and Mars," said GNS Science.
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A caldera is a large volcanic depression resulting from the collapse of a volcano due to emptying of its magma chamber after eruption or magma withdrawal.
The group of scientists began studying the Philippine continental shelf in 2008, before turning their focus in 2015 to study the features of the Benham Rise, a seismically active region below the Philippine Sea.
The discovery of the caldera raises questions about what special conditions caused it to form, around 40 million years ago.
The group's findings were published in the journal Marine Geology.
"We are delighted that our findings have been published as no other caldera of this size has been discovered before," Barretto said.
"The next step is for us to confirm that this is indeed a volcanic caldera through rock sampling and geophysical studies."
If the team's findings are confirmed by further research, Apolaki will officially become the largest known caldera on Earth.