It hads to have an original design and unique features.
One example is the Greek amphitheater. It is designed in a way that amplifies the sound of the speaker standing on the stage such that everyone sitting in the amphitheater can hear him clearly.
It should have a sustainable design which helps to decrease the cost of maintenance and energy.
One example is the NTU School of Art, Design and Media building. It has a verdant turfed roof which blends with the ground contour. Environmentally, it helps to lower the roof temperature and surrounding areas.
The design of the building must be nice and leave a memorable impression on people.
One example is the Burj Al Arab building in Dubai. It features an iconic sail-shaped design which is very memorable