Ali Barati wants to know about the tallest building in the world. The answer to this question is less clear than you might think.

Disputes over the answer to this question have to do with whether tall tower structures can be included as buildings. Is a communications tower a building? Do the metal antenna devices on top of some buildings count as additional height? What about structures that are partly under water?

Or, communication towers that are supported by metal wires? No matter the answer, a building in Dubai, United Arab Emirates, will be the tallest above-ground structure in the world when it is completed next year.

The Burj Dubai is expected to measure six hundred ninety-three meters tall, not counting a spire at the very top. The current height of the Burj Dubai is about six hundred meters. Its more than one hundred sixty levels will contain homes, offices, shops, and a hotel.

To make sure this building in Dubai will really be the tallest in the world, we checked with the Council on Tall Buildings and Urban Habitat. This organization is based in Chicago, Illinois. It includes building designers, engineers and planning experts. The group’s aim is to provide useful information on planning and building tall buildings around the world.

The council says a building’s height is measured from the sidewalk level of the main entry to the structural top of the building. But the council says it looks at other ways to measure height as well.

These include from the sidewalk to the highest floor of a building, to the top of the building’s roof covering, or to the top of the antenna or spire on the top of the building. Designers of the Burj Dubai have made sure that it is the tallest in all four ways of measuring.

Before the Burj Dubai, the tallest free-standing building in the world was the CN Tower in Toronto, Canada. That tower measures five hundred fifty-three meters.

And, the tallest structure in the world is currently a television transmission antenna in the American state of North Dakota. It extends six hundred twenty-eight meters into the sky. But it will not be the tallest structure for long.