Make the cherry simple syrup. To do this, combine all the ingredients in a medium sized saucepan. Bring to a boil, and then reduce to a simmer for about 20 minutes. After 20 minutes, remove from heat and set aside to cool. Once it's about room temperature, strain and store the liquid in an airtight container in the fridge.
Add 3/4 cup cherry simple syrup (or more if you prefer a sweeter drink), 1 cup lime juice, and 4 cups water in a pitcher and stir to combine. Serve with crushed (or cubed) ice and garnish with lime and/or cherries if you'd like!