secret stash can safe from Altoids tin, this would be a great way to hide house keys too! Just nail it under the deck, or someplace similar in the garden.
Shipping Container Bunker how to (where I live has frequently has really nasty weather, along with droughts for the past decade which has harmed our trees)
Secret Storage Space
Secret compartment wall safe disguised as electrical wall outlet
Lock the track on your home's garage door when you go away on vacation. First heard this idea from my dad!
Hidden Storm shelter
Smart idea ... as a student I have that kind of thing on hand already :)
secret trap door in stairs
Old book spines glued to a box. Great idea for a hidden bookshelf storage.
This is an old trap door that lead to a secret room at Castle Menzies