A dwell cam is like a special camera that watches things and takes pictures or videos of them while they are still or not moving. It is used to help keep an eye on places or things that might need to be watched all the time, like a building or a street. Imagine your parents putting a camera in your room so they can make sure you're safe and sound while they're not there. That's kind of like what a dwell cam does, except for buildings and objects!