The large building in the foreground is the London Guarentee Building and it is one of four buildings that were constructed around the Michigan Avenue Bridge during the early 1920s. Directly behind the London Guarentee Building is Mather Tower, and the form of this "needle" skyscraper was encouraged in the 1923 Chicago Zoning Ordinance which called for tall, slender towers. 35 East Wacker Drive Building (to the right of Mather Tower) is lit up at night, and was one of the tallest buildings in the US when it was built in 1925.