Education is mandatory for pupils between the ages of 6 and 15. After Kindergarten, which is not compulsory, follows the mandatory primary school until the age of 12. Secondary education is available in two cycles, Compulsory Lower Level Secondary Education offered at Gymnasiums and Post-compulsory, Upper Secondary Education which is offered by the Unified Lyceums and Technical Vocational Educational Institutes. Tertiary education is divided into university education and non-university education, which is offered by Higher Technological Educational Institutes and Higher Education Institutes. Postgraduate courses are also available at Tertiary education level. Greece and especially Athens has a large offer of international schools.