CATHERINE ELLIS, REPORTING: There are the tallest buildings in the world, there are works of art that have become famous icons and tourist attractions for countries.
There are famous sports stadiums, temples and ancient monuments.
Throughout history countries have competed to have the biggest, the tallest or most unusual buildings.
But architecture's certainly not as simple as coming up with a creative design - there's lots to think about!
For starters where's it going? There might be a river or trees in the way!
And how solid is the ground? Look what can happen if you don't think about that!
Another thing is the environment. In Darwin your design would need to be cyclone proof - in China there's earthquakes to think about.
What building materials would you use to keep the place warm in winter and cool in summer? Where should the windows go to let enough light in?
A design must also function well for the people using it.
Take the MCG for example, it has to cater for sport and huge rock concerts with crowds of around 100,000 people.
There needs to be enough toilets, stairs, lifts, and cafes.
The big screens and scoreboard are positioned so everyone can see and the sirens are strategically placed so everyone can hear, but you don't go deaf!
The design of music and theatre venues is really important because it can affect the sound you hear - it's called acoustics.
CATHERINE: These days with problems like climate change, architects also have to think about making designs more environmentally friendly.
It's something these kids have been learning all about.
They've been designing ways to save water at their schools.
ABBIE, STUDENT: At the bottom there's a container that when it's full of water it tips into the underground water tank, which the hose waters the plants and if there's too much water it goes into this water tank.
Some kids worked out that lots of water's wasted because of drinking fountains so they came up with new designs.
CHELSEA, STUDENT: We have this catcher so if water leaks it comes down here and into the pipe and into this tank and we could use the tank water for other things, maybe for gardening or hosing.
Kids also added trees, water friendly plants, timed taps - that allow just enough water for you to wash your hands, dual flush toilets and logs to stop run-off.
JESS, STUDENT: We put more plants and big trees and the garden boxes in because then we can have the natural environment with the built environment.
They now realise Architects have lots to consider, but the idea of being able to leave your footprint with a building you designed, would be pretty amazing.
