Watermelon-Mint Agua Fresca

1. Combine mint leaves, sugar and 1/4 cup water in a small pot. Bring to a boil and stir until sugar has dissolved. Transfer mixture to a heatproof container and chill, uncovered, until cool, about 30 minutes.
2. Strain mint syrup into a blender; discard mint leaves. Add watermelon and lime juice and blend until very smooth.
3. Using a fine-mesh sieve, strain into a pitcher; discard solids.
4. Add 2 cups water and stir well to combine.

Add a bit of color to the drink by adding fresh mint sprigs.