What is this? We have this strange hole in our house, its more of a...

We have this strange hole in our house, its more of a chamber hole, its resembling a safe, but not really, if you get what i close-fisted. Its about 30 cm in length, and have a key hole to open it, except near is no key. The house is over 50 years old, and we hold never been able to clear it. i looks like a photo frame, you have the border and after the glass, in that sort if shape.

What could it be?
What is it usually used for?
Could near be anything in it like a map, gold ingots...

Thanks, the people before us, never told us what be in it. Thanks

we cannot open it and we dont want a lockmith, we in recent times want to know the questions, thanks.

More info than finishing and the girl about pirates was amazing please hold on to going with more of your theories, thanks.
Has anyone used the Riddex Pro, Bell &...
Its your very own Chamber of Secrets.
JUNK contained by FRONT OF HOUSE?! HELP?!?
oh man. try breaking it if you really want to know.

I Bought a shade that you hold to...
resourcefully it could be and old celler but i dont think there's any gold ingots in it try prying it open?
Gardening backing needed, blatant pupil, easiest veggies to...
It's a priest hole for a terrifically very small priest
I own a rat within my room but......
Answers:    It's a gateway to Narnia.

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Or a out of danger. Which seems more likely?