Determining the world's tallest structure has generally been an uncomplicated task. Inconsistencies arise, when it comes to defining the world's tallest building or the world's tallest tower, the reason being - failure to identify a structure as a building or a tower and that which is being measured.

The Council on Tall Buildings and Urban Habitat (CTBUH) made four classifications in which the world's tallest building can be measured:

1. Height to the structural or architectural top (including spires and pinnacles, but not antennas, masts or flagpoles)
2. Height to the highest occupied floor
3. Height to the top of the roof
4. Height to the top of antenna

The mashup below, presents the currently standing tallest skyscrapers measured to their architectural tops (first of the categories defined by CTBUH)