Combine the red wine, sweet vermouth, grenadine, and cranberry juice in a large pitcher.
Stir gently to mix all the flavors together.
Add ginger ale and watermelon syrup to the mix.
Stir again, ensuring that everything is well combined.
Wash and slice the orange and strawberries.
Add these to the pitcher, and ensure the fruit is evenly distributed.
Add ice cubes to the pitcher to chill the sangria.
Allow it to settle for a while so the flavors can blend well.
Pour the sangria into glasses, filling each with a mix of drink and fruit.
Garnish the glasses with additional fruit slices, if desired.