Nymphaea alba, White Water-lily http://en.wikipedia.org/wiki/NymphaeaceaeThese are wonderful in the pond, a domestic variety here. the fish go under them during the brightness of the day. I took this one during a rain, if you notice a bug is using it for protection. These are easy to propagate. Just take parts of a rhizomes with a tip and a bit of fiber root on the end and replant it into a pot.
Hint here. when planting or fertilizing do not buy the fertilizers that are sold for these. Waste of money actually. In the bottom of the planter place about 6 cm of decomposing leaves and then add heavy soil almost clay like on top of it. It is free and so much better. Bigger leaves, and more larger blooms then you ever will get with the pill at the store.