Police are treating as suspicious the discovery of a body close to a tourist hotspot in central London.
A member of the public found a man with injuries in Hyde Park shortly before 6am.
The victim was dead when officers arrived at the scene on Friday, the Metropolitan Police said.
Police set up a cordon spanning an area the size of two football pitches in the park following what an officer at the scene called an "unexplained death".
The body, which is close to Speakers' Corner, could be seen under a tree, as investigators in white crime scene suits erected a tent over it.
At least 30 officers were at the scene.
One officer was heard telling a member of the public that the incident "happened in the last couple of hours and we are trying to get to the bottom of it".
In a statement the force said: "This incident is being treated as suspicious. No arrests have been made and enquiries are ongoing."
The Met said next of kin have not yet been informed and asked anyone with information to contact them.
Investigators in blue suits could be seen searching the vast cordon as they placed markers in a trail across the scene.
Police later extended the cordon - increasing it to double its initial size - as their investigations continued.
The man's body has yet to be moved from the scene.
A man who lives close to the park, who gave his name only as Lee, said: "I was walking with my dog and it was very obvious there was a lot going on up ahead of me.
"Once I got there I realised there was a major crime scene - they were in the midst of finishing taping it off.
"Under the trees I could just make out what appeared to be a body with an aluminium blanket over it."
Discovering the incident at around 7.15am, he said seeing a body in the park where he takes his pet on a daily basis came "as a bit of a shock".
He added: "When you're up early and walking the dog you don't think you're going to stumble across all the police and a crime scene like that."
The 45-year-old added: "It's just not a nice thing."