I'll bet you a dollar to a donut that you looked through one of these as a kid. What am I?

Mountains birthed me, wind made me fly, I drown your feet where oceans lie. Kids build castles from my skin, Time itself is trapped within. What am I?

I hold water, not food, for outdoor travelers Strapped to their belt, I’m an essential companion I am often made of plastic or metal Though I once could be made of gourds or leather

Where dust and dog-eared secrets lie, a quiet keeper up high. Wood or metal, it's no elf, holds the tales on itself.

I guard what you want to keep, Behind a door that’s small and neat. A secret code may set me free, But without it, locked I’ll be. I hold your treasures out of sight. What am I, keeping them safe and tight?