In Judaism, there are some mitzvot you do three times a day, like tefillah (prayer.) Some come once a week, like shabbat (sabbath,) some once a month, like Birkat Levanah (the blessing of the new moon) some once a year, like the fast on Yom Kippur (the day of atonement.) Some come once in a lifetime, like a wedding (well, hopefully only once.) And some come once in history, like Hashem's directive to the Jewish slaves in Egypt that they slaughter a lamb on the eve of Pesach.
One of the rarer mitzvot is Birkat HaChama (The blessing of the sun.) Once every twenty eight years, the planets and sun are aligned exactly as they were at the instant of the creation of the sun, at least according to the biblical narrative. At the sight of this unusual and wondrous occurrence, one is to recite Birkat Chama. Birkat HaChama happened to fall on Erev Pesach (Passover Eve) this year, so in addition to all the other holiday preparations, tens of thousands flocked to the Old City of Jerusalem to perform the mitzvah.
Reading the bracha sheet.
The sun is in position. It's go time!