Originally Posted by
GreaseMonkeySRT
Corners are preferred as it blocks access to the sides and corners of the safe as those are usually the most vulnerable, and from being easily tipped over to make prying easier. Any RSC (residential security container) gun safe can be cut into with a powered sawz all pretty quickly. Bolt it down to the concrete, and adding a cinder block wall on the exposed side isn't a bad idea. People have also expressed the opinion that having multiples safes is a good idea, as it's not a one and done scenario as far as breaking in goes.
What elwarpo said about fire and water is the truth.