A tower viewer is a kind of gadget that helps you see things that are far away, like tall buildings or mountains. It's like having a special pair of eyes that can see really far!
Here's how it works: the tower viewer has lenses inside that magnify the view you're looking at. When you look through the viewer, you can adjust the lenses to make things look closer or farther away. You can also move the viewer around to get a better view of what you want to see.
Tower viewers are often found in observatories or on top of tall buildings, where people can use them to see the city or the scenery around them. They make it easier to spot details that you wouldn't be able to see with just your regular eyes. Plus, they're really fun to use and make you feel like a detective!