How does that grab you? Nymphaea 'Alaska' hardy waterlily.
When I was attending Oklahoma State University our faculty would often bring in guest speakers on a wide variety of subjects. One speaker was a well known Oklahoma City Landscape Architect: Tommy Roberts. If my memory serves me correctly (this was in 1978), Mr. Roberts had a few trademarks he generally used in all his designs. The one trademark I remember the most was that all his pools were designed with dark bottoms. This created much visual depth and surface reflection. Night lighting was exceptional. The image above was taken over my stock tank pool which I painted black before installation.