ATLANTA & RIYADH, Saudi Arabia–(BUSINESS WIRE)–The United States of America has signed its Participation Contract for Expo 2030 Riyadh, marking a significant milestone in the World Expo’s preparations and further strengthening the momentum for international participation in the global event. The signing marks an important step in the United States’ journey towards Expo 2030 Riyadh, paving the way for the development of its pavilion, programming and visitor experience. It also reinforces the g