This riddle asks you to think less literally: What has a start and an end but no middle?
Answer: A road.
A road can have a defined starting point and an ending point, while there does not have to be one officially defined place called “the middle.” You can calculate a halfway point, of course, but unlike its endpoints, the “middle” is not necessarily a named or fixed part of the road.
That distinction is the wordplay behind the riddle. The question is not asking whether something can mathematically have a halfway point; it is asking for something commonly described by where it starts and where it ends.
