Queen Khamphoui greeting Lao and White Hmong women. King Savang Vatthana (tallest person) and other dignitaries, including Prime Minister Souvanna Phouma (black beret) and Col. Phan Siharat (hatless, white suit), are present. Sam Thong was the USAID refugee operations center for northeastern Laos from 1962 until its fall on March 20, 1970.