Design of buildings is important according to architectural textbooks. At its roots, architecture exists to create the physical environment in which people live, but architecture is more than just the built environment, it’s also a part of our culture. It stands as a representation of how we see ourselves, as well as how we see the world. There are poorly designed buildings, but also some great building works. In the Victoria Era, architects designed buildings based on bricks and other materials. The design of flaws was based on lighting as it would not only affect appearance but also health conditions. The materials that buildings are made of also matter. For example, the design of ground floors must ensure that the building is able to withstand the weight of the higher levels. In the 20th century, many old buildings with design flaws were demolished or modified through a natural selection process, which means they are an altered state rather than an original state. This is an application of Darwin's theory of natural selection to modification of old buildings, which means buildings should adapt to the new world to survive, or be pulled down. So, it's argued to be unfair to criticize the demolition, although some people believe that whether to be remained should be decided based on their nature and functions. As the world became more and more connected, the styles evolved, but even in modern construction, there is still an importance in honouring the cultural nuances in the built environment.