ANKARA - The 20th International Izmir Festival will open today in this Aegean city and run until August 20 with concerts at Ephesus Roman Theater and at Celsus Library. The Mediterranean Youth Orchestra - conducted by Jacques Mercier and composed of 85 musicians from 15 countries who have been coming together on vacation times since 1984 - will perform at the closing concert to be held at Pergamon (Bergama) Asklepieon Theater. The Harmonic Band of the Turkish Armed Forces performs a free concert for the opening of 20th International Izmir Festival. The opening concert of the festival will be held at the Great Theater, Ephesus; "The Turkish Five Under the Baton of Renowned Five Conductors". Chich Korea, Omara Portuondo, Ian Anderson and Yamato - Japanese Drummers are among the performers of the festival.