A lone diver explores an underwater world using torches as he dives into a vast cavern.
The underwater caves and passages are around 40ft deep and are completely dark with the only light coming from collapsed cave chambers.
Inside the limestone caves, caverns and passages are stalactites - an icicle-shaped formation created from minerals - which have formed to be more than 2m long.
Photographer Franco Banfi spent four days exploring the Tucatan Peninsula's Riviera Maya, in Mexico, with each dive into the underwater systems taking around two hours.
© Franco Banfi/Solent News & Photo Agency
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