(CNN) If they looked up, passersby in central London on Monday got a strange and unsettling sight: 84 men, standing silently on the rooftops of office towers as if they were about to leap to their deaths.

Except these men aren't actually human. They are life-size sculptures, placed there to raise awareness about suicide.

The sculptures were installed overnight as part of Project 84 , an idea made possible by American street artist Mark Jenkins and the Campaign against Living Miserably , or CALM, a charity focused on preventing suicide, which it says is the single biggest killer of men under 45 in the UK.

The sculptures represent the 84 men who commit suicide, on average, each week in the UK. CALM says three in four suicide victims are men.

"As a society we have to move past embarrassment and awkwardness, we have to face this awful issue, discuss it and actively work to stop it," said CALM CEO Simon Gunning.

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