AON and One Prudential Plaza Buildings

The Aon Center and One Prudential Plaza Buildings are two impressive skyscrapers located in downtown Chicago, US. The Aon Center, formerly known as Amoco Building, rises 858 feet (262m) tall and is the fifth tallest building in the US and the second tallest in Chicago. It was designed by Edward Durel Stone and Harry Weese and became the world's tallest marble-clad building upon its completion in 1973. The One Prudential Plaza is just 38 feet (11.6m) shorter and is the fourth tallest building in the city. It is clad in granite and aluminum and was designed by Edward Durel Stone, who also designed the Aon Center. Both buildings boast great views of Grant Park, Millennium Park, Lake Michigan and the Chicago skyline. They offer public access to their observation decks (97th floor of Aon Center and 66th floor of One Prudential Plaza) from which visitors can admire sweeping views of the city. Tourists can also access to the first floor of the main lobbies.