He played John Lennon's "Imagine" -- and then rode off.
It was part of Davide Martello's mission "to promote peace."
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Martello, or "Klavierkunst," played in France after terrorist attacks killed 130 people, and in Ukraine during pro-Russian unrest in 2014, WFAA reports.
According to his website, he wants to play in every capital of the world with his grand piano.
The "colours of his piano keys" -- black and white -- made him come to Dallas on Sunday, he wrote on Facebook earlier Sunday.
He wrote, "I will play in front of the memorial to promote peace."