Take watermelon into a blender
Cover and puree it until smooth
Strain through a fine mesh sieve
Take sugure and half cup water in a saucepan
Boil it in medium-high heat until sugar dissolve
Stir 3 cups of cold water and the lemon juice
Devide ice into 10 glasses
Scoop 2 to 3 tablespoons of watermelon puree over the ice
Then top with lemonade
Gently stir and serve
