Having been captured early (1862) in the American Civil War by the Union Army, the reconstruction of New Orleans was marked most notably by the occupation of Union troops until 1878. Six years later, in 1884, the city advertised to the world that its troubles were over by hosting the World's Centennial Cotton Exposition in what is now Audubon Park. The residual effect of the exposition was the attention drawn to the uptown area of the city as a desirable place to reside. The population explosion started immediately following the exposition. Massive immigration to the United States during the period of 1880 thru 1920 due to economics, famine and oppression along with the fact that New Orleans was the second largest port in the United States led to many immigrants from far away locations such as Ireland, Italy and Germany settling in the uptown area.