Smallest in the world

 Smallest continent........................................... Australia

Smallest ocean...................................................... Arctic

Smallest republic................................................... Nauru

Smallest colony................................................ Gibraltar

Smallest state...................................................... Vatican

Smallest landmass................. TheAustralian Mainland

Smallest bird............................................ Humming bird

Smallest flowering plant...................................... Wolfia

Smallest planet................................................ Mercury

World's Smallest Museum........................ Arizona, US

World's Smallest PC      Space Cube