Think about it...Your great grandpa who lived centuries ago and who is still knownfor the great inventions he made in the past wrote you a letter!Ali Qushji the space engineerAl-Biruni the famous mathematicianEvliya Chelebi the travellerAl-Farabi the second teacher in the worldHezarfen Ahmed Chelebi the first aircraft engineer andIbn Khaldun the most important historian and philosopher of the world wrote you a very special letter. It is very exciting isn't it?When you read these letters you will both travel to the timesyour grandpas lived in and learn about their wonderful works.Come on kids! Now it is time to read the letters from our "Wise Grandpas"...