Chicago Walking Tour: Historic Skyscrapers. Explore the Loop's famous architecture during this 2-hour walking tour with an expert guide from the Chicago Architecture Foundation. Discover the beginnings of the Chicago School of Architecture through visits to some of the city's oldest skyscrapers, dating from the late 19th and early 20th centuries. This sophisticated, informative tour is a must-do for history and architecture buffs. Book and Save 22%! Chicago Walking Tour: Historic Skyscrapers.