There are 2 religious events (Eid) in a year for Muslims and their timing changes every year according to the Moon Calendar. Turkey use Sun Calendar which is international one. But Islam follows Moon Calendar. So, Days come 10 days earlier every year.

Ramadan Eid which takes 3 days after Ramadan Month. Only schools, banks, all official places are closed in these 3 days. But Restaurants Cafes, Bars, sights, museums are all open. Grand Bazaar and Spice Bazaar are closed during Ramadan Eid in Istanbul.

Sacrificing Eid is 2 months later after Ramadan Eid which takes 4 days. Only schools, banks, all official places are closed in these 3 days. But Restaurants Cafes, Bars, sights, museums are all open. Grand Bazaar and Spice Bazaar are closed during Sacrificing Eid in Istanbul