The Rotunde in Vienna's Leopoldstadt district was a building erected for the 1873 Vienna World's Fair. The building was a partially covered circular wrought iron construction, 84.1 m (276 ft) tall, with a diameter of 107.83 m (353.8 ft). While the Rotunda stood, its dome was the largest in the world, larger than the Pantheon in Rome. Not until 1957, 20 years after the Rotunda fell, was a larger dome built: the dome of Belgrade Fair – Hall 1, which is only about 1 m larger in diameter.

The 1873 Vienna World's Fair was the large world exposition that was held from 1 May to 31 October 1873 in the Austria-Hungarian capital Vienna. Its motto was "Culture and Education".