A gesture associated with the Nazis has a surprising history. But in Germany, there was little doubt about its meaning.

Elon Musk wasted little time creating controversy following the swearing-in of Donald Trump as the 47th President of the United States on Monday. While speaking following the swearing in, Musk thanked the crowd, then put his hand to his chest and thrust it toward the crowd.

Musk, 53, spoke to a crowd of Trump supporters at Capital One Arena in Washington, D.C., after Trump was sworn in at the U.S. Capitol. While thanking the supporters, Musk put his right hand over his heart, then extended his arm out with his palm down. He then turned around and repeated the gesture.