May 5th and 6th every year Keresteci Hakki Sokak and Cankurtaran Mahalesi celebrate one of the biggest street carnival in Istanbul

known as Hidrellez

In the folk calendar used by the people, the year used to be divided into two: The period between May 6 and November 8 was summer, called the “Days of Hızır”, and the period between November 8 and May 6 was winter, called the “Days of Kasım”. May 6 thus represents the end of winter and the start of the warm days of summer, a cause for celebration.
There are various theories about the origin of Hızır and Hıdrellez. Some of these suggest that Hıdrellez belongs to Mesopotamian and Anatolian cultures, and others that they belong to pre-Islamic Central Asian Turkish culture and beliefs. However, it is impossible to ascribe the Hıdrellez festival and beliefs surrounding Hızır to a single culture. Various ceremonies and rituals have been performed for the arrival of spring or summer in Mesopotamia, Anatolia, Iran, Greece and in fact all eastern Mediterranean countries since ancient times.