What you need:
First you need to make the syrup. To do this boil the water and the sugar. Once it comes to the boil take off the heat and leave to cool.
Put some watermelon, an amount of your choice, and the syrup in a blender and blend. Put the mixture into the freezer until it turns into a slushy like texture - this can take up to 3 hours.
Spoon in your watermelon slushy into a glass. Place ice and lime slices on top. Cover in lemonade and there you have a refreshing drink