770 - A Brief History
The previous Rebbe, Rabbi Yosef Yitzchok Schneerson, came to America on the ninth of Adar II 5700 (March 20, 1940), after miraculously escaping from Nazi-occupied Poland. For six months he stayed at the Greystone Hotel in Manhattan, NY where he had a suite that was used as a Shul in addition to his living quarters.
Finally, on the 5th of Av, a fitting residence was located, and negotiations
were started to purchase the building at 770 Eastern Parkway. A week later
on Friday, 12 days in Av, the purchase was completed, and the Rebbe was
given the keys. A few days later the Rebbe came to 770 and prayed Mincha
and Maariv there. He then said, "The One Above should allow it to be a
permanent dwelling for the soul, for Torah study and for prayer services,
but a temporary dwelling for living purposes. For very soon we should
merit to be in the Holy Land with Moshiach."