From the ancient times people built large buildings but of the eldest we don’t have enough information to say which was the tallest building in the world in that period. Lighthouse of Alexandria from the 3rd century BC was tall, but its true height is not known today. The Great Pyramid in Egypt was the tallest structure in the world for a very long time but it is not considered a building. Before the skyscrapers of today, from 1200s to 1870s the tallest buildings were Christian churches and cathedrals. Most of them were on the territories that belonged to England and Germany. When the skyscrapers appeared the tallest one were in New York City and Chicago for some 130 years until the title started wearing buildings on the eastern hemisphere. The tallest building in the world today is Burj Khalifa in Dubai.
When determining which the world’s tallest building rule is that a built structure is a “building” which means that it is regularly inhabited or occupied. Structure has to be designed for residential, business or manufacturing purposes and has to have floors. Somewhere there are churches and cathedrals and if they are buildings is a subjective matter. Height is also subjective and while some take “height of the highest floor” as a criterion, some other take "height to the top of any part of the building". “Council on Tall Buildings and Urban Habitat” take "height of the architectural top of the building", which includes spires but not antennae, masts, or flag poles.
From the 1200s until 1901, the world's tallest building was always a church or a cathedral. Tallest buildings than them didn’t exist at the time. The first one was Old St Paul's Cathedral in London, with its spire of 149 meters, which was completed in the 1200s. The next one was Lincoln Cathedral of 159.7 meters, finished in 1300. Other were, chronologically: St. Mary's Church (151m),Strasbourg Cathedral (142m), Church of St. Nicholas (147m), Rouen Cathedral (151m), Cologne Cathedral (157.38 m), and Ulm Minster (161.53m) built in 1890 and held the title of the tallest building until 1901.
In the second half of the 19th, a new kind of structure started appearing, the one that used iron or steel internal structure to bear the building's weight. That technique allowed for much taller buildings than before. In 1901 Philadelphia City Hall was finished and, with 167 meters, it was taller than Ulm Minster. From that moment on, skyscrapers take the lead. Singer Building was built in 1908 in New York City and was 186.57m high. Other tallest buildings in the world in chronological order are: Metropolitan Life Tower (213.36m),Woolworth Building (241m), Bank of Manhattan Trust Building (283m), Chrysler Building (319.9m),Empire State Building (381m), World Trade Center #1 (417m), Sears Tower (442m), Petronas Towers (451.9m), Taipei 101 (509.2m), and Burj Khalifa (828m) finished in 2010. Some of them were also the tallest structure ever built at the time of their completion. Burj Khalifa is still both the tallest building and the tallest structure ever built.