Dubai

A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries passengers and a source of heat, in most cases an open flame caused by burning liquid propane. The heated air inside the envelope makes it buoyant since it has a lower density than the colder air outside the envelope. As with all aircraft, hot air balloons cannot fly beyond the atmosphere. Unlike gas balloons, the envelope does not have to be sealed at the bottom, since the air near the bottom of the envelope is at the same pressure as the surrounding air.

In modern sport balloons the envelope is generally made from nylon fabric and the inlet of the balloon (closest to the burner flame) is made from a fire resistant material such as Nomex. Modern balloons have been made in all kinds of shapes, such as rocket ships and the shapes of various commercial products, though the traditional shape is used for most non-commercial, and many commercial, applications.

Tourism is travel for pleasure or business; also the theory and practice of touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tours. Tourism may be international, or within the traveller’s country. The World Tourism Organization defines tourism more generally, in terms which go “beyond the common perception of tourism as being limited to holiday activity only”, as people “traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes”.

Dedicated road bicycles have drop handlebars and multiple gears, although there are single and fixed gear varieties. Road bikes also use narrow, high-pressure tires to decrease rolling resistance, and tend to be somewhat lighter than other types of bicycle. The drop handlebars are often positioned lower than the saddle in order to put the rider in a more aerodynamic position. In an effort to become more aerodynamic, some riders have begun using aerobars.

And when aerobars where invented is unclear but they seem to date back to the early 1980s. The light weight and aerodynamics of a road bike allows this type of bicycle to be the second most efficient self-powered means of transportation, behind only recumbent bicycles due to the latter’s higher aerodynamic efficiency.

Mountain bikes fitted with slick or semi-slick are also popular for commuters. Though less efficient, the upright riding position allows the cyclist a better view of traffic, and they can also be readily fitted with mudguards, cargo racks and other accessories. Mountain bikes are usually ridden on unpaved roads and tracks but they are not to be confused with cyclocross bikes.