A pair of peregrine falcons has raised two chicks in central London - for the first time in many years.
The breeding pair have two chicks
The birds of prey have settled on a University of Westminster building south of Regent's Park.
Peregrine falcons are now rare enough to enjoy the same international level of protection as the giant panda.
The public is being invited to view the birds from telescopes in the park on Marylebone Green this week.
The bird's numbers were severely reduced in the past by the use of the pesticide DDT.
It has recently made a comeback, with about 1,400 pairs in the UK - up by 600 in two years.
Other pairs have been spotted in London, but have not been recorded as breeding.
Only one other breeding pair has been seen - in Battersea, south London, in the past few years.
Pete Massini, of English Nature, said London provided plenty of food for the birds in the form of a good supply of pigeons.
He said the city's tall buildings mimicked their natural habitat of cliff tops.
But he warned peregrine falcons were easily disturbed when nesting.
People in nearby buildings should minimise disruption to breeding birds, he said.
"We expect there to be at least 10 breeding pairs in London in the future," he added.
"So look out and look up - towers of steel and glass are not the only new things on the London skyline."