If you look in the right places, you can often see animals in their homes.
Take a "Home Sweet Home" hike and see how many animal homes you can find.
Look in trees for birds' nests, squirrels' holes, and wasps' nests. Hollows inside trees are squirrels' favorite kind of home, but squirrels sometimes build nests out of leaves high in a tree. You can see these nests in the winter after the leaves fall.
Even if you live in a city or suburb, it's likely that there are opossums and/or raccoons living in your neighborhood. Opossums may "den" in a hollow log or under a bush or house. Raccoons like to live in hollow trees, but when they choose to live near humans, they tend to live very close by. They often spend their days sleeping hidden in attics or garages, or under porches.
You'll know you've found a den if you find fur the animal has shed and maybe some tidbits of leftover food. Tell an adult so the animal can be safely removed and taken to a more natural area. Unless an animal has invaded your house, never disturb an animal's home. It could harm the animal, and it could be unhealthy for you.