Imagine a city made entirely of glowing white buildings. In 1904, the Louisiana Purchase Exposition opened in St. Louis, Missouri. Most people called it the World's Fair. It covered 1,272 acres, making it the largest world's fair ever held at that time. Over seven months, nearly 20 million people visited. The fair was built to celebrate the 100th anniversary of the Louisiana Purchase. Countries from around the world constructed elaborate buildings called pavilions to display their art, culture, and technology. The fair featured one of the largest art exhibitions in history. Over 9,000 paintings, sculptures. Other artworks filled the Palace of Fine Arts. That massive building still stands today as the St. Louis Art Museum. Visitors could see works by artists from Europe, Asia, and the Americas all under one roof. The fair also introduced Americans to foods and inventions that became part of daily life. Ice cream cones, iced tea, and cotton candy were all popularized at the 1904 fair. The fairgrounds had gardens, fountains, and buildings in a classical style with columns. At night, thousands of electric lights made the buildings glow white. Many visitors had never seen electric lighting, and the glow earned the fairgrounds the nickname "The Ivory City."