Thirty-seven countries participated in Philadelphia’s 1876 Centennial Exposition, an earlier anniversary event related to America250. The international participation helped present the United States as an industrial and technological power.
The exposition ran in Fairmount Park from May through November 1876. Its exhibits included machinery, manufactured goods, agricultural products, art, science, and inventions. Countries built displays or contributed objects showing their industries and cultural achievements.
The fair was organized to celebrate the 100th anniversary of the Declaration of Independence, but it also served as a showcase for contemporary innovation. Alexander Graham Bell demonstrated an early telephone, and visitors encountered products and technologies that became important parts of modern life.
The number 37 refers to participating countries, not U.S. states. The exposition also included state buildings, commercial displays, and federal exhibits, so totals can vary depending on whether a question counts countries, states, buildings, or exhibitors.