What are chinampas and what were they used for?

Chinampas are man-made islands, not super big or super small. They were constructed out of mud, sticks, dirt and wooden poles (to keep it in place). They are sometimes referred to as 'floating island". They were made and used in the Aztec empire around their swampy island. The chinampas were used for growing crops. Almost of the the empires food was grown from the chinampas.