A body has been found in the Serpentine lake in London's Hyde Park.
Police divers dragged the body from the lake at lunchtime after a walker spotted it in the water.
Visitors walking through the park on the warmest day of the year so far were told to move away as police put a cordon up around the immediate area.
The Metropolitan Police said the man's death was being treated as "unexplained".
A worker at the park, who did not want to be named, said: "We had a few customers out on the lake and someone pointed out that there was something over there so I went and had a look.
"It was just floating on the other side of the island. It was caught on one of the chains."
A Scotland Yard spokesman said: "We were called at around 1250 BST to the Serpentine to reports a body had been seen.
"Marine support teams recovered a man's body."