Okay kiddo, imagine you're outside on a sunny day. The sun is very bright in the sky and there are no clouds to block it out. Now, normally the sun sets in the evening, and it gets dark outside. But, in some places, something special happens. In the summer, the sun never really sets! This happens in the North and South poles of the Earth, which are very far away from where we live.
So, when it's summertime in the North Pole, the sun doesn't go all the way down below the horizon at night. It just hangs out a little bit above the horizon, making it bright all night long. This is called the 'midnight sun'. It's like a really late night and early morning all at the same time!
This happens because of the way the Earth is tilted. You see, the Earth is kind of like a spinning top. It spins around really fast, which is what gives us day and night. But, it's also tilted a little bit on its axis, which means that in different parts of the world, the sun shines at different angles. So, when it's summer in the North Pole, the sun shines there for a really long time!
Isn't that cool? So, if you ever travel to the North Pole in the summertime, don't be surprised if it's bright outside at midnight!