Peel off the labels from the sweetened condensed milk cans. Place them into a 6-8 quart pot. Add enough water to cover the cans completely.
Bring the water to a boil. Turn the cans upside down every 30 minutes for 3 hours.
After 3 hours of boiling, place the cans in a cool water bath until you can handle the can without burning yourself.
Open all of the cans and put the caramel into a large mixing bowl. Using a hand held mixer, blend all three cans until the caramel is smooth. Put mixture into the pie crust. Put caramel pie in the freezer for a few hours to firm up.
Serve cold and top each slice with whip cream and nuts or even miniature chocolate chips.