Philadelphia City Hall

Philadelphia City Hall is the world’s largest free standing masonry building made of brick, white marble, limestone and granite and functions as the seat of government for the city of Philadelphia, Pennsylvania. In 1976 was designated a National Historic Landmark and in 2006, also named a National Historic Civil Engineering Landmark by the American Society of Civil Engineers.
The building was designed by Scottish-born architect John McArthur Jr. and Thomas Ustick Walter in the Second Empire style, and was constructed from 1871 to 1901 at a cost of $24 million. City Hall's tower was completed by 1894, although the interior wasn't finished until 1901. Designed to be the world's tallest building, it was surpassed during construction by the Washington Monument and the Eiffel Tower. Upon completion of its tower in 1894, it became the world's tallest habitable building. It was also the first secular building to have this distinction, as all previous world's tallest buildings were religious structures, including European cathedrals and—for the previous 3,800 years—the Great Pyramid of Giza.