In 1881 the largest building West of the Mississippi opened on the soggy edge of a tenacious frontier town. For over eighty years, Denver Union Station bore witness to a procession of arrivals and departures that transformed the Rocky Mountain West. From 19th century regional gateway to 21st century multi-model hub, Denver Union Station: Portal to Progress tells the story of the grand era of railroad travel and the awe inspiring structure that stands today at the crossroads of past glory and future promise.