Apparently, an octopus has blue blood which is pumped around its boneless body by three hearts. Rays breath through holes behind their eyes, and seahorses can look backwards and forwards at the same time.
And those are just some of the creatures of the deep that await visitors at Berlin's Aquadom and Sea Life Centre.
Sea Life as become a phenomenon in several countries, possibly because it is the only place where you can get up close and personal with a shark with absolutely no risk of personal injury.
Combining education, wonder and conservation, it's a place you will want to return to. So, it's a good job they do annual passes which allow unlimited entry to all eight Sea Life Centre's in Germany.