(Every year, a field near York creates an amazing maze out of maize, nice little homophone there. The reason it's temporary is that maize is an annual crop, so they plant it in May, cut the pathways in June, open the maze once it is big enough to get lost in in July, then they have to harvest it in September, and plough the field in order to start again with a new design the next year. Unfortunately it isn't free, but it is fun.)