In a large pot, place the can of sweetened condensed milk with the label removed, in the pot.
Cover the can with water.
Cook on high heat until the water comes to a boil, then reduce the heat to medium/high and simmer for 4 hours, adding water as needed to keep the can covered.
Step 2: Assembling the Pie
Carefully open the can and pour the caramelized sweetened condensed milk into the prepared graham cracker crust.
Cool the pie in the refrigerator until completely chilled.
Step 3: Topping
Once the pie is cooled, top it with the thawed frozen whipped topping.
Step 4: Serving
Serve the caramel pie, and enjoy the delightful combination of caramel and whipped topping.