Why is there a Chinese-inscribed stone in the Washington Monument?

Inside the Washington Monument, there's a commemorative stone with Chinese inscriptions.

During his visit to China this May, U.S. President Donald Trump mentioned the stone at a state banquet, bringing this unusual piece of history back into the public view in both China and the United States.

More than a symbol of friendship between the Chinese and American peoples, the stone reflects a cultural connection and goodwill between the two peoples that stretches back more than a century.