Experts searching for the remains of Charles Darwin's ship HMS Beagle have revealed the outline of the dock where it was probably dismantled.
The vessel circumnavigated the globe twice and Darwin was on board when he made the discoveries that led to his theory of natural selection.
A team, commissioned by Historic England, made the finding on the mud flats of the River Roach in Essex.
It said no evidence of the Beagle itself has yet been found.
The team from Wessex Archaeology used a drone fitted with a specialist camera to investigate the area off Paglesham, near Southend-on-Sea.
Its investigation builds on previous work undertaken a team led by the late Dr Robert Prescott from the University of St Andrews in 2003, and more recent work by the University of Southampton.
Earlier studies had identified the site the as the possible final resting place of the vessel, first launched in 1820.
Darwin was aboard the ship on its second great voyage between 1831 and 1836 to survey the South American coast and the Galapagos Islands.
Following the Beagle's third and final exploratory voyage in 1843 it was refitted as a static watch vessel for the coastguard in 1845, until sold in 1870.
Historic England said it "would've been leaking like a sieve" so was broken up "either in situ in the mud dock in the 1870s or was hauled out and actually lies under the boat shed".
Dr Dan Atkinson, director of coastal and marine at Wessex Archaeology, said it was likely the vessel was dismantled at the dock, and lots of the material would have been taken and repurposed elsewhere.
He said: "We know from previous surveys that there are the remains of potentially substantial material in the dock - this could be the remains of the dock itself, another vessel possibly associated with the local oyster fishery, or the Beagle - we can't say for sure."
Further analysis of data may tell them more, he said.
Historic England commissioned the team to research the area ahead of the bicentenary of the vessel's launch in May 2020.
For more on this story, watch BBC Inside Out East at 19:30 GMT on Monday 28 October, and afterwards on the iPlayer.