Life-sized naked statues are taking up vantage points across London in a display by the artist who created The Angel of the North.
The sculptures were cast from Anthony Gormley's body
The 31 sculptures of Anthony Gormley will stand atop buildings and public walkways to highlight a show of his work at the Southbank starting in May.
Mr Gormley said the project was in recognition of the vast numbers of people living in cities.
His show Blind Light at the Hayward Gallery runs from 17 May to 19 August.
Owners of more than 100 buildings were asked to take part in the project.
Sites which were finally chosen include the Shell Centre, the National Theatre, Waterloo Bridge, King's College, Imperial College and Freemasons' Hall.
Mr Gormley said: "The idea was to somehow introduce these life-sized figures into the topography of London as if it were a natural landscape, as if it were mountains against the sky.
"I just wanted to recognise that now, it's said, that over 50% of the human population on this planet now live within the city...a totally constructed humanly made environment and what that means."
All the figures, which are cast from the sculptor's body, are planned to be in the eye line of visitors to the exhibition.
The display - Event Horizon - is one of London's most ambitious public art commissions.
Viewed from the vantage point of the Hayward, the works will be spread over a 1.5 sq km area, with some figures clearly visible and others sensed only as presences on the horizon.
Mr Gormley said it was designed to "get under people's skin" and make them "feel slightly uncertain about what's going on in the world that you are living in".