Yom Yerushalayim, Jerusalem Day
The newest holiday on the Jewish calendar celebrate the reunification of Israel's capital.
Yom Yerushalayim--Jerusalem Day--is the most recent addition to the Hebrew calendar. It is celebrated on the 28th day of Iyar (six weeks after the Passover seder, one week before the eve of Shavuot). Although Jerusalem has been considered the capital city of the Jewish people since the time of King David--who conquered it and built it as the seat of his monarchy in approximately 1000 B.C.E.--there has never been a special day in honor of the city until the Israeli army took over the ancient, eastern part of the city on the third day of the Six-Day War in June 1967.
Shortly after the Six-Day War, "a municipal unification" of the two sections of the city took place, ending 19 years of separation between predominantly Arab and Jewish suburbs of Jerusalem, following the War of Independence in 1948.
A Young Holiday
Due to the young age of this holiday, there is still not much which makes it unique in terms of customs and traditions. It is gradually becoming a "pilgrimage" day, when thousands of Israelis travel (some hike!) to Jerusalem to demonstrate solidarity with the city. This show of solidarity is of special importance to the state of Israel, since the international community has never approved the "reunification" of the city under Israeli sovereignty, and many countries have not recognized Jerusalem as the capital of the Jewish State (The United Nations "partition plan" of November 1947 assigned a status of "International City" to Jerusalem).
The Israeli education system devotes the week preceding this day to enhancing the knowledge of the history and geography of the city, with a special emphasis on the unique role that it played in Jewish messianic aspirations since Biblical times.