Make Your Own Hide-A-Key Glue a rock to the top of a empty pill bottle, bury the bottle so that only the rock shows. A spare key is hidden inside! - 15 Secret Hiding Places That Will Fool Even the Smartest Burglar OR it could be a Geocache!
A secret storage in a staircase can be a great hidden storage for bulky things that look unflattering when stored in full display. It’s the same space under stairs only hidden and accessed from the floor in the staircase. At: The Bottom Of The Stairs