21 Kislev is celebrated annually by Satmar chasidim worldwide as the day R’ Yoel Teitelbaum Zt’l the founder of Satmar Chasidis in America, escaped from Hungary and this year marks the 71th anniversary of the Grand Rebbe’s escape from the Nazis.
This video from Satmar Kuf Alef Kislev celebration By Rabbi Aron Teitelbaum and his Chasidim At NY State Armory in Crown Heights, Brooklyn. December 2, 2015.