The definition of architecture is the art or science of building, often with a focus on habitable structures. We are familiar with architects like Gehry, Wright, and Gaudi as well as famous buildings like the Empire State Building in New York and the Burj Khalifa in Dubai. But are habitable structures a requirement? Actually, it can be much broader than that. For instance, the Eiffel Tower, the pyramids in Egypt, interiors of cathedrals or the main hall at New York's Grand Central Station are all examples of world-famous architecture. In addition, examples of architecture do not have to be world famous. Private houses, bridges etc. are all examples and skylines may represent a collection of similar or different types of architecture.