In an old-fashioned glass, combine the sugar, water and Angostura Bitters® with a bar spoon. Next, add half the Bacardí 8 Años along with 2-3 large ice cubes, stirring repeatedly. Pour in the second half of the rum and 2-3 more ice cubes, continuing to stir. Cut a piece of orange peel (about 5 cm long); express the orange peel over the drink, releasing the citrus oils; drop the peel into the drink to finish.