A memorial to journalists killed while doing their work has been unveiled by UN Secretary General Ban Ki-moon.
The 10m (32ft) glass and steel cone on top of BBC Broadcasting House in central London will shine a beam of light into the sky every night at 2200.
It is dedicated to all news journalists and those who have worked with them, including drivers and translators.
Over the past 10 years an estimated two war reporters per week have died, with many more killed covering corruption.
Relatives of some of the victims joined the UN secretary general for the dedication ceremony.
The memorial's inauguration follows the recent deaths of two BBC journalists, Abdul Samad Rohani and Nasteh Dahir Faraah, in Afghanistan and Somalia.
Mr Ban said it stood "in tribute to all those who have sacrificed their lives so that the rest of us could be informed".
"But it is also for those who survive, those who are out there right now - risking their lives to report what they uncover in the face of deadly threats," he added.
Rodney Pinder, director of the International News Safety Institute (INSI), which works for more safety for journalists, said: "These men and women are the unsung heroes of democracy, for without a free press there can be no freedom.
"This shaft of light in the capital of international journalism is a visual reminder of their sacrifice."
BBC Chairman Sir Michael Lyons drew attention to the risks taken by many journalists in the course of their work.
He said: "The implicit contract, whereby journalists place their lives at risk to help us understand the world and its events better, needs to be reaffirmed.
"At moments like this that sacrifice is properly valued and the loss is widely shared."
The sculpture, entitled Breathing, is by Spanish artist Jaume Plensa.
It was specially commissioned and selected as a result of an international competition for the BBC's public art scheme.
The BBC also commissioned a poem to complement the structure by ex-war correspondent and poet, James Fenton.