If you haven't already, grind the graham crackers in a food processor, blender or in a ziploc with a rolling pin.

Heat the oven to 350, and grease a 9x13" baking dish.

In a large bowl stir together the graham cracker crumbs, butter, sugar, and salt.

Press the crust mixture into your greased baking dish and bake for 8-10 minutes, or until slightly golden.

Remove from the oven and allow to cool on the counter while you prepare the filling.

In a large mixing bowl, combine the sweetened condensed milk, and eggs.

Add the lime juice and zest and whisk thoroughly.

Fold in the blackberries, being careful not to break them.

Pour into the baked crust and place in the oven.

Bake for an additional 12-15 minutes.

Remove from the oven and allow to cool completely and then refrigerate at least 30 minutes until set.