Where was the Marquis de Lafayette buried, and why was Bunker Hill soil placed in his grave?

The Marquis de Lafayette is buried at the Picpus Cemetery in Paris, France.

In accordance with his final wishes, his grave was covered with soil from Bunker Hill. He and his son had collected this earth during his final visit to the United States in 1824–1825, a gesture intended to symbolize his enduring connection to the American cause and the American Revolution, in which he served as a major general and became known as the "Hero of Two Worlds."1