The United States government is calling for people to give their views on the protected status of the Marianas Trench.
The Marianas Trench Marine National Monument is among 27 monuments in various states and territories up for review after President Donald Trump's executive order signed last month.
He instructed a review of all national monuments that were created by past presidents using the Antiquities Act.
The Marianas Trench area includes submerged lands and waters of the Northern Marianas and Guam.
It was declared a marine national monument under President George W Bush in 2009.
The Department of Interior has opened a 60 day public comment period.