Nine months is nothing: African elephants have the longest pregnancy of any mammal, which can last up to two years. Scientists don’t really know why it takes so long to grow an elephant, but it could have something to do with their highly developed brains—elephants have complex social relationships and cognitive skills.

As the value goes up, heads start to swivel, and sceptics soften. Starting a new currency is easy. Anyone can do it. The trick is getting people to accept it.

Kilankwa, Federal Capital Territory, Nigeria