Who knows the secrets of the giant squid? Nobody! Well, nobody knows all of them – nobody really knows how big they can get or much about their life cycles and habits way down in the ocean murk. What we know about them comes mostly from their carcasses, washed up with scars that bear witness to titanic undersea struggles with other squid, or whales, or who knows what.

This element of mystery is why giant squids are here. They’re a reminder of a time, not very long gone, when the animal kingdom was full of mysteries, when it was all too easy to observe the creatures we knew and imagine larger, fiercer, more freakish and more toothy versions somewhere out there in the unexplored wilds. Now the wilds – on land at least – are well mapped, and mystery is the province of hopeful or desperate Yeti-hunters and bigfoot-believers. The last large mammal to be discovered was the somewhat pitiful Okapi, in 1911, and even he is a cross between two other, better-loved beasts. The okapi was nominated for this list and quickly dismissed. For a taste of the unknown the way our ancestors may have felt it we must look to the seabed, and to the beaches where its monsters sometimes wash ashore.