Traditional Colombian Limonada Natural Recipe?

On a recent trip to Colombia, I tried a traditional non-alcoholic beverage served in almost all restaurants and eateries. It was called Limonada Natural. It was a type of sweetened limeade... but it was frothy.... sooooooo delicious. I tried a few ways of making it but just can't get it quite the same. I searched everywhere for it and can't find it!!! HELP!!! :)