The south tower was once the tallest in Europe. The tower became low quite quickly because new ones were built and every large church competed with another with the height of its towers. Austrians tried to restore the former glory, but they did not have enough money, so they finished the construction of the northern tower with a small dome.
Extremely recommend spending two hours in Vienna with guide Tom. He tells the stories of the city and its history in the short, interesting and elegant way. The trip starts from Stephan Platz, passes through the streets of Graben, the Jewish quarter, Am Hof and ends at Ferstel Palace and the Mekler cellar.