The use of thankfully to mean 'fortunately', 'let us be thankful (that)', is still disliked by many people, although it is becoming accepted. In this sense it is separated from the rest of the sentence by a comma. Thankfully they went to their grandfather's that day means that they went there full of gratitude; Thankfully, they went to their grandfather's that day means that it was fortunate that they did so; They went to their grandfather's, thankfully, that day means it was fortunate that they went on that particular day.
The crescent is a symbol of Islam and the green also denotes Islam. The four stars and the four stripes of colour represent the four islands in the group (including Mayotte, which is a French dependency). Effective date: 2002.