The idea of celebrating Teachers' Day took root in many countries during the 20th century; in most cases, they celebrate a local educator or an important milestone in education (for example, Argentina has commemorated Domingo Faustino Sarmiento's death on 11 September since 1915,[2] while India has celebrated the birthdate of Dr Sarvepalli Radhakrishnan (5 September) since 1962).[3] This is the primary reason why countries celebrate this day on different dates, unlike many other International Days.