1947 vintage postcard. As the 19th century came to a close, the Congress Plaza Hotel and Convention Center opened in 1893 as the Auditorium Annex, built by famous hotel developer R.H. Southgate. With its unique façade as the centerpiece, the elaborately designed hotel soon became a favorite among Chicago’s captains of industry, society, politics, and culture. This vintage linen lithograph print postcard would look great framed or make a nice addition to any collection.