A 7-foot-tall portrait of Russian President, Vladimir Putin, made from bullet shells is on display as part of an exhibition that opened in New York on Thursday, and it's meant to be a sobering reminder of the horrors of war.

The shells are all from the 2014 Ukrainian uprising known as the Maidan Revolution, one of the bloodiest European conflicts since the early 1990s. And the two Ukrainian artists who created the portrait fiercely believe Putin is to blame for the violence that tore apart the eastern part of their country.

"Russia tried to pull us into the USSR," Daniel Green, one of the artists said. "It was a line between democracy or totalitarianism." Both Green and his fellow artist, Daria Marchenko, took part in the uprising.

Green said several of his friends were killed in the fighting. That's what gave him the idea of using spent bullets to symbolize what was happening.