Expo '74 was the World's Fair held at this 100-acre site from May to November 1974 during a period of growing environmental awareness and concern over pollution, endangered species, and care for the planet. Motivated by Spokane's centennial, a declining economy, suburbanization, and pollution of the Spokane River, a broad group of business and civic leaders led by King Cole worked to improve the site, open the city to the river, and create an international visitor destination. The Union Pacific, Burlington Northern, and Milwaukee Road railroads deeded real estate to Spokane for the fair and the city's future, and after extensive marketing efforts Spokane was recognized by the Bureau of International Expositions as the smallest city ever to host a world's fair. President Richard Nixon opened Expo '74 and President Gerald Ford closed it. More than 5 million visitors attended from around the world under the theme “Celebrating Tomorrow's Fresh New Environment,” and countries including the U.S., China, the U.S.S.R., and Australia hosted pavilions introducing visitors to their culture and natural environment. Decades later, the site still serves as a venue for cultural events, community gatherings, and access to the natural world, and the fair is credited with changing the face of Spokane forever.