Please answer a question about the following article about John Kerry:

On April 22, 1971, Kerry appeared before a U.S. Senate committee hearing on proposals relating to ending the war. The day after this testimony, Kerry participated in a demonstration with thousands of other veterans in which he and other Vietnam War veterans threw their medals and service ribbons over a fence erected at the front steps of the United States Capitol building to dramatize their opposition to the war. Jack Smith, a Marine, read a statement explaining why the veterans were returning their military awards to the government. For more than two hours, almost 1000 angry veterans tossed their medals, ribbons, hats, jackets, and military papers over the fence. Each veteran gave his or her name, hometown, branch of service and a statement. Kerry threw some of his own decorations and awards as well as some given to him by other veterans to throw. As Kerry threw his decorations over the fence, his statement was: "I'm not doing this for any violent reasons, but for peace and justice, and to try and make this country wake up once and for all."

What did Kerry do on Apr 22, 1971?
appeared before a U.S. Senate committee hearing