An exhibition in Dubai is celebrating the history and future of the so-called \"megatower.\" Love them or hate them, there is no denying they are impressive feats of engineering. But do they actually create sustainable and community-oriented ways of living, or are they little more than viewing platforms providing tourists with a view from the clouds? Opinion is often divided. The Middle East region seems to be a particular fan of these structures, with the 828-metre Burj Khalifa in Dubai currently standing proud as the tallest man-made structure in the world. It will not be long, however, before its crown is taken by neighbouring country Saudi Arabia, which is planning to build a tower more than one kilometre high. The designer of the under-construction Kingdom Tower, Adrian Smith, also happened to be the chief architect of the Burj Khalifa. He is something of an industry genius when it comes to creating larger-than-life towers. But when it comes to these towers, all is not what it seems. It is not actually the megastructures themselves that make the money, it is the surrounding land that is developed according to what is known as a masterplan. Downtown, The Dubai Mall and The Address Hotel are all part of the Burj Khalifa\'s masterplan and are the real money makers. In an interview on American television just after it was announced that Smith had won the contract for Kingdom Tower, he explained the thinking behind such structures. \"I think if you take an individual super-tall building by itself, they are usually not money makers. \"This one is projected to make a little bit of money. Burj Khalifa had made some money, but the real money is to be made in the land surrounding the tower. Once a tower like this goes up, the land around it becomes much more valuable.\" This maybe goes some way to explaining Middle Eastern countries\' apparent fascination with these buildings - they are countries where space is not an issue. In other countries and cities that are already established with little free space, the idea of a megatower is no longer feasible. The buildings themselves are not always simply about altering the skyline or filling a gap in the office space or apartment market, they can help a city make a name for itself. \"In my opinion, towers like this are about attracting attention,\" says Dubai-based Arvin Daeizadeh, a sustainability consultant who worked on the Burj Khalifa in a previous role. \"When you break a record like the Burj Khalifa did - which it didn\'t break by a little but, it broke it by almost 200 per cent - it draws a lot of attention worldwide. \"In the early 2000s, the Burj Al Arab put Dubai on the map, people identified Dubai with that building.\" The lesser versions of the mega- towers, the skyscrapers, also divide opinion between those that think they provide excellent high-density housing, and those that think they lack character and community. In Dubai, for example, very few of them are built with any outdoor public space apart from a swimming pool. Even so, from a sustainability point of view, Daeizadeh says, they are the best option. \"They limit sprawl, urbanisation and suburbanisation, which becomes inefficient and ineffective because of the amount of infrastructure needed. \"You need more roads, more sewer lines, people have to commute and the carbon footprint goes up. If everyone lives in a smaller locale, it is more sustainable.\" With the world\'s population - currently about seven billion - expected to jump to nine billion in the next 20 or so years - skyscrapers may be the only sustainable way forward. \"You can\'t expect people to spread out and have villas and backyards. They either have smaller quarters or live more compact,\" Daeizadeh says.