In 1979, the National Christmas Tree was only partially lit. When President Jimmy Carter sent his daughter Amy to light the tree on December 13, the switch lit only the star atop the National Christmas Tree, while the state trees on the Pathway of Peace were illuminated only by tiny blue lights. Carter told the surprised crowd that the National Christmas Tree would remain dark until the American hostages in Iran were set free. The theme of the tree was "Hope and Light", which celebrated the 100th anniversary of Thomas Edison's invention of the practical incandescent light. The tree itself was trimmed with silver balls and white garland, and a complex, changing lighting scheme (also in white) designed. There were only 50 smaller trees that year (one for each of the hostages), and a single tree separate from the Pathway of Peace representing prisoners of war. Only nine days of musical performances were planned.