After my visit, I can say it is not for all. It will be mostly appreciated by those who love applied science or students coming from intensive science subjects in their lower years.
Location: 500 Harris Street, Ultimo, NSW, 2007, Australia
Located in the old Ultimo Power Station building adjacent to Darling Harbour, the Powerhouse Museum is the flagship venue of Museum of Applied Arts and Sciences (MAAS). Its unique and diverse collection spans science, technology, design and decorative arts, engineering, architecture, health and medicine, fashion and contemporary culture.
Seems to small from the outside but has a lot to offer on their underground levels which stores the permanent exhibition.
On Text: Railways were a powerful symbol of industrial progress, transformed the landscape and the way people viewed the world.
One of the featured/temporary exhibition during my visit is about shoes. How nice of them to have interactive spots for kids to color and do paper folding to create shoes. (*Still looking for Johanna's Secret..)
Back to the permanent exhibition on space and transportation:
Where to buy the souvenirs and returning present (pasalubong/omiyage)? You can buy it anywhere but the lowest prices can still be found in Paddy's.
Location: Market City, Hay Street & Thomas Street, Sydney NSW 2000, Australia
What to see in Town Hall area?
St Andrew's Cathedral
St Andrew's Cathedral is the cathedral church of the Anglican Diocese of Sydney in the Anglican Church of Australia [wiki]
Town Hall at night during Vivid Sydney Festival.
The famous QVB - Queen Victoria Building which has great architecture from the outside and expensive shops from the inside.