What is "selectividad"

Selectividad is the popular name given to the Spanish University Access Tests ("Prueba de Acceso a la Universidad", P.A.U.), a non-compulsory exam taken by students after secondary school, necessary to go into University. Students must take six 90 minutes written exams over three days in June or September, consisting of common and specific subjects taken in "Bachillerato" (the last two non-compulsory years of secondary education). Selectividad exams are set by the Public Universities of each Autonomous Community and enable accessing the Spanish university system.